Biomedical subjects

M Bagchi

Publications and source records attributed to M Bagchi.

At least 37 records · Page 2Linked to original sources

PubMed2001

Protective effects of antioxidants against smokeless tobacco-induced oxidative stress and modulation of Bcl-2 and p53 genes in human oral keratinocytes.

The oral use of chewing tobacco has greatly increased in recent years, and this usage is associated with cancers of the mouth, lip, nasal cavities, esophagus and gut. Oral cancer accounts for 3% of all cancers in U.S.A. and is the seventh most common cancer. Previous studies in our laboratory have demonstrated the protective abilities of a novel IH636 grape seed proanthocyanidin extract (GSPE) against reactive oxygen species both in vitro and in vivo models, and provided significantly better protection as compared to vitamins C, E and beta-carotene. In the recent past, we have demonstrated smokeless tobacco (STE)-induced oxidative stress, apoptotic cell death in a primary culture of normal human oral keratinocytes (NHOK), and have compared the protective abilities of vitamins C and E, singly and in combination, and GSPE in this pathobiology [Free Rad. Biol. Med., 26, 992-1000 (1999)]. In the present study, we have assessed the protective role of vitamins C and E, and GSPE against STE-induced modulation of intracellular oxidized states in NHOK cells as demonstrated by laser scanning confocal microscopy. Approximately 11%, 26%, 28% and 50% protection were observed following incubation with vitamin C, vitamin E, a combination of vitamins C plus E, and GSPE, respectively. DNA fragmentation was assessed as an index of oxidative DNA damage and similar results were observed. Furthermore, the cellular viability and functional roles of Bcl-2, p53 and c-myc genes were assessed in STE-induced oxidative stress in NHOK cells. NHOK cells were treated with STE (0-200 micrograms/ml) for 24 h and changes in the expression of Bcl-2, p53 and c-myc genes were measured by reverse transcriptase-polymerase chain reaction (RT-PCR), and the protective effect of GSPE was assessed. Approximately a 2.0-fold increase in p53 gene expression was observed following incubation of the oral keratinocytes with 100 micrograms/ml of STE, beyond which the expression of p53 decreased, confirming increased apoptotic cell death with a higher concentration of STE as reported earlier. GSPE significantly modulated STE-induced changes in p53. The expression of antiapoptotic Bcl-2 gene decreased with STE treatment and the expression of Bcl-2 gene increased significantly following preincubation with GSPE. No significant change in the expression of transcription factor c-myc gene responsible for cell cycle growth was observed following incubation with STE and/or GSPE. Thus, c-myc may not be involved in STE-induced cytotoxicity towards NHOK cells. These results suggest that antioxidant protection of STE-induced cellular injury is associated with alterations in Bcl-2 and p53 expression.

Antioxidants↗

PubMed2001

A heat shock transcription factor like protein in the nuclear matrix compartment of the tissue cultured mammalian lens epithelial cell.

This investigation characterizes a prominent nuclear matrix protein isolated from tissue cultured mouse lens epithelial cells. The nuclear matrix protein was isolated using a modified Penman technique. Total nuclear matrix proteins were further separated by SDS-polyacrylamide gel electrophoresis. The SDS-PAGE profile of the nuclear matrix proteins displayed a prominent doublet band at 60 kDa region. Nonequilibrium 2D gel electrophoresis revealed that this protein is a basic nuclear protein. This 60 kDa protein was further characterized by comparing its internal peptide amino acid sequence with known protein sequence using the BLAST technique, and this study demonstrated that 60 kDa nuclear matrix protein displays significant sequence similarity with Xenopus Laevis heat shock transcription factor. We also raised antibodies against 60 kDa nuclear matrix protein. Immunofluorescence, studies showed that this 60 kDa nuclear matrix protein preferably decorates nucleus, and puncted pattern of fluorescence suggest presence of this protein in the discrete areas of the nucleus. Heat shock transcription factors upregulate synthesis of heat shock proteins and many of these protein act as molecular chaperones. Thus, presence of a nuclear matrix protein with significant sequence similarity with heat shock transcription factor suggests sustained heat shock protein synthesis in the mouse lens cells.

Amino Acid Sequence↗

PubMed2001

Protection against drug- and chemical-induced multiorgan toxicity by a novel IH636 grape seed proanthocyanidin extract.

Grape seed proanthocyanidins have been demonstrated to exhibit a broad spectrum of pharmacological, therapeutic and chemoprotective properties. In our previous studies, IH636 grape seed proanthocyanidin extract (GSPE, commercially known as ActiVin) demonstrated excellent concentration- and dose-dependent free radical scavenging abilities in both in vitro and in vivo models and provided significantly better protection than vitamins C, E and beta-carotene. GSPE demonstrated significant cytotoxicity towards human breast, lung and gastric adenocarcinoma cells, while enhancing the growth and viability of normal human gastric mucosal cells and macrophage J774A.1 cells. In this study, the bioavailability and protective ability of GSPE were examined against acetaminophen-induced hepatoxicity, amiodarone-induced pulmonary toxicity, doxorubicin-induced cardiotoxicity, cadmium chloride-induced nephrotoxicity, dimethylnitrosamine-induced spleenotoxicity and O-ethyl-S,S-dipropyl phosphorodithioate (MOCAP)-induced neurotoxicity in mice. In each experiment, half of the test animals were orally fed GSPE for 7-10 days prior to drug/chemical exposure, while the other half received no GSPE. Parameters of analysis included changes in serum chemistry [alanine amino-transferase (ALT), blood urea nitrogen and creatine kinase], histopathology and integrity of genomic DNA. The results indicated that GSPE preexposure prior to the drugs/chemicals such as acetaminophen, amiodarone, doxorubicin, cadmium chloride or dimethylnitrosamine treatment, provided near complete protection in terms of serum chemistry changes (ALT, blood urea nitrogen and creatine kinase) and inhibition of both forms of cell death, e.g., apoptosis and necrosis. DNA damage in various tissues triggered by these agents was significantly reduced. Histopathological examination of the organs evaluated reflected similar patterns to those of the serum chemistry and DNA results. MOCAP exposure showed symptoms of severe neurotoxicity coupled with serum chemistry changes in the absence of any significant genomic change or brain pathology. GSPE afforded only partial protection in the brain tissue. These results suggest that GSPE exposure is bioavailable and provides significant multiorgan protection against drug- and chemical-induced toxic assaults.

Alanine Transaminase↗

PubMed2001

Oxidative mechanisms in the toxicity of chromium and cadmium ions.

Chromium and cadmium are widely used industrial chemicals. The toxicities associated with both metal ions are well known. However, less information is available concerning the mechanisms of toxicity. The results of in vitro and in vivo studies demonstrate that both cations induce an oxidative stress that results in oxidative deterioration of biological macromolecules. However, different mechanisms are involved in the production of oxidative stress by chromium and cadmium. Chromium undergoes redox cycling, while cadmium depletes glutathione and protein-bound sulfhydryl groups, resulting in enhanced production of reactive oxygen species such as superoxide ion, hydroxyl radicals, and hydrogen peroxide. These reactive oxygen species result in increased lipid peroxidation, enhanced excretion of urinary lipid metabolites, modulation of intracellular oxidized states, DNA damage, membrane damage, altered gene expression, and apoptosis. Enhanced production of nuclear factor-kappaB and activation of protein kinase C occur. Furthermore, the p53 tumor suppressor gene is involved in the cascade of events associated with the toxicities of these cations. In summary, the results clearly indicate that although different mechanisms lead to the production of reactive oxygen species by chromium and cadmium, similar subsequent mechanisms and types of oxidative tissue damage are involved in the overall toxicities.

Animals↗

PubMed2001

Chromium (VI)-induced oxidative stress, apoptotic cell death and modulation of p53 tumor suppressor gene.

Chromium (VI) is a widely used industrial chemical, extensively used in paints, metal finishes, steel including stainless steel manufacturing, alloy cast irons, chrome, and wood treatment. On the contrary, chromium (III) salts such as chromium polynicotinate, chromium chloride and chromium picolinate, are used as micronutrients and nutritional supplements, and have been demonstrated to exhibit a significant number of health benefits in rodents and humans. However, the cause for the hexavalent chromium to induce cytotoxicity is not entirely understood. A series of in vitro and in vivo studies have demonstrated that chromium (VI) induces an oxidative stress through enhanced production of reactive oxygen species (ROS) leading to genomic DNA damage and oxidative deterioration of lipids and proteins. A cascade of cellular events occur following chromium (VI)-induced oxidative stress including enhanced production of superoxide anion and hydroxyl radicals, increased lipid peroxidation and genomic DNA fragmentation, modulation of intracellular oxidized states, activation of protein kinase C, apoptotic cell death and altered gene expression. In this paper, we have demonstrated concentration- and time-dependent effects of sodium dichromate (chromium (VI) or Cr (VI)) on enhanced production of superoxide anion and hydroxyl radicals, changes in intracellular oxidized states as determined by laser scanning confocal microscopy, DNA fragmentation and apoptotic cell death (by flow cytometry) in human peripheral blood mononuclear cells. These results were compared with the concentration-dependent effects of chromium (VI) on chronic myelogenous leukemic K562 cells and J774A.1 murine macrophage cells. Chromium (VI)-induced enhanced production of ROS, as well as oxidative tissue and DNA damage were observed in these cells. More pronounced effect was observed on chronic myelogenous leukemic K562 cells and J774A.1 murine macrophage cells. Furthermore, we have assessed the effect of a single oral LD50 dose of chromium (VI) on female C57BL/6Ntac and p53-deficient C57BL/6TSG p53 mice on enhanced production of superoxide anion, lipid peroxidation and DNA fragmentation in the hepatic and brain tissues. Chromium (VI)-induced more pronounced oxidative damage in p53 deficient mice. This in vivo study highlighted that apoptotic regulatory protein p53 may play a major role in chromium (VI)-induced oxidative stress and toxicity. Taken together, oxidative stress and oxidative tissue damage, and a cascade of cellular events including modulation of apoptotic regulatory gene p53 are involved in chromium (VI)-induced toxicity and carcinogenesis.

Animals↗

PubMed2001

Evaluation of cysticercus fasciolaris antigen for the immunodiagnosis of neurocysticercosis.

Cysticercus cellulosae antigen has been frequently used to detect antibodies for immunodiagnosis of neurocysticercosis. We have, for the first time, used membrane extract of cysticercus fasciolaris, the larval stage of Taenia taeniaeformis, in ELISA, with successful results. IgM and IgG antibodies against cysticercus were measured in serum from cases of neurocysticercosis (217), normal and diseased controls (89). 203 sera from cases of neurocysticercosis were positive for either or both IgG and IgM antibodies while 157/217 cases showed IgM and 158/217 showed IgG antibodies. Ten controls showed false postivity in IgG ELISA. Eight of these cases also had IgM antibodies. The test had an overall sensitivity of 93.54% and a specificity of 84.2% with a positive predictive value of 93.54% and a negative predictive value of 84.2%. Cysticercus fasciolaris can be conveniently produced in the experimental laboratory host, Rattus rattus, and would be of practical value in the immunodiagnosis of cysticercosis in humans.

Animals↗

PubMed2001

Benefits of resveratrol in women's health.

Resveratrol and trans-resveratrol are powerful phytoestrogens, present in the skins of grapes and other plant foods and wine, which demonstrate a broad spectrum of pharmacological and therapeutic health benefits. Phytoestrogens are naturally occurring plant-derived nonsteroidal compounds that are functionally and structurally similar to steroidal estrogens, such as estradiol, produced by the body. Various studies, reviewed herein, have demonstrated the health benefits of phytoestrogens in addressing climacteric syndrome including vasomotor symptoms and postmenopausal health risks, as well as their anticarcinogenic, neuroprotective and cardioprotective activities and prostate health and bone formation promoting properties. Conventional HRT drugs have been demonstrated to cause serious adverse effects including stroke and gallbladder disease, as well as endometrial, uterine and breast cancers. Recent research demonstrates that trans-resveratrol binds to human estrogen receptors and increases estrogenic activity in the body. We investigated the effects of protykin, a standardized extract of trans-resveratrol from Polygonum cuspidatum, on cardioprotective function, the incidence of reperfusion-induced arrhythmias and free radical production in isolated ischemic/reperfused rat hearts. The rats were orally treated with two different daily doses of protykin for 3 weeks. Coronary effluents were measured for oxygen free radical production by electron spin resonance (ESR) spectroscopy in treated and drug-free control groups. In rats treated with 50 and 100 mg/kg of protykin, the incidence of reperfusion-induced ventricular fibrillation was reduced from its control value of 83% to 75% (p < 0.05) and 33% (p < 0.05), respectively. Protykin was seen to possess cardioprotective effects against reperfusion-induced arrhythmias through its ability to reduce or remove the reactive oxygen species in ischemic/reperfused myocardium. Taken together, these data suggest that trans-resveratrol supplementation may be a potential alternative to conventional HRT for cardioprotection and osteoporosis prevention and may confer other potential health benefits in women.

Animals↗

PubMed2000

Chemopreventive effects of grape seed proanthocyanidin extract on Chang liver cells.

In an attempt to ameliorate the chemotherapy associated normal cell toxicity, in this study a known antioxidant, grape seed proanthocyanidin extract (GSPE) using Chang liver cells has been used. Chang liver cells were treated in vitro with idarubicin (Ida) (30 nM) and 4-hydroxyperoxycyclophosphamide (4-HC) (1 microg/ml) with or without proanthocyanidin (25 microg/ml). The cells were grown in vitro and the growth rate of the cells were determined using MTT assay. The results showed that the GSPE decreased growth inhibitory effects of Ida and 4-HC on Chang liver cells in vitro. Since these chemotherapeutic agents are known to induce apoptosis in the target cells, these cells were also analyzed for presence of apoptotic cells using flow cytometry. The GSPE decreased the number of apoptotic cell population induced by either chemotherapy. In an attempt to determine the mechanisms of ameliorating effects of proanthocyanidin, the expression of apoptosis/cell cycle/growth related genes, Bcl-2, p53 and c-myc was determined in the treated and control cells using Western blotting or reverse transcriptase-polymerase chain reaction (RT-PCR) techniques. There was an increased expression of Bcl-2 in the cells treated with GSPE. However, there was a significant decrease in the expression of other cell cycle related genes such as p53 and c-myc in these cells following treatment with GSPE. Thus, these results indicate that proanthocyanidin can be a potential candidate to ameliorate the toxic effects associated with chemotherapeutic agents used in treatment of cancer.

Anthocyanins↗

PubMed2000

Free radicals and grape seed proanthocyanidin extract: importance in human health and disease prevention.

Free radicals have been implicated in over a hundred disease conditions in humans, including arthritis, hemorrhagic shock, atherosclerosis, advancing age, ischemia and reperfusion injury of many organs, Alzheimer and Parkinson's disease, gastrointestinal dysfunctions, tumor promotion and carcinogenesis, and AIDS. Antioxidants are potent scavengers of free radicals and serve as inhibitors of neoplastic processes. A large number of synthetic and natural antioxidants have been demonstrated to induce beneficial effects on human health and disease prevention. However, the structure-activity relationship, bioavailability and therapeutic efficacy of the antioxidants differ extensively. Oligomeric proanthocyanidins, naturally occurring antioxidants widely available in fruits, vegetables, nuts, seeds, flowers and bark, have been reported to possess a broad spectrum of biological, pharmacological and therapeutic activities against free radicals and oxidative stress. We have assessed the concentration- or dose-dependent free radical scavenging ability of a novel IH636 grape seed proanthocyanidin extract (GSPE) both in vitro and in vivo models, and compared the free radical scavenging ability of GSPE with vitamins C, E and beta-carotene. These experiments demonstrated that GSPE is highly bioavailable and provides significantly greater protection against free radicals and free radical-induced lipid peroxidation and DNA damage than vitamins C, E and beta-carotene. GSPE was also shown to demonstrate cytotoxicity towards human breast, lung and gastric adenocarcinoma cells, while enhancing the growth and viability of normal human gastric mucosal cells. The comparative protective effects of GSPE, vitamins C and E were examined on tobacco-induced oxidative stress and apoptotic cell death in human oral keratinocytes. Oxidative tissue damage was determined by lipid peroxidation and DNA fragmentation, while apoptotic cell death was assessed by flow cytometry. GSPE provided significantly better protection as compared to vitamins C and E, singly and in combination. GSPE also demonstrated excellent protection against acetaminophen overdose-induced liver and kidney damage by regulating bcl-X(L) gene, DNA damage and presumably by reducing oxidative stress. GSPE demonstrated excellent protection against myocardial ischemia-reperfusion injury and myocardial infarction in rats. GSPE was also shown to upregulate bcl(2) gene and downregulate the oncogene c-myc. Topical application of GSPE enhances sun protection factor in human volunteers, as well as supplementation of GSPE ameliorates chronic pancreatitis in humans. These results demonstrate that GSPE provides excellent protection against oxidative stress and free radical-mediated tissue injury.

Animals↗

PubMed2000

Role of p53 tumor suppressor gene in the toxicity of TCDD, endrin, naphthalene, and chromium (VI) in liver and brain tissues of mice.

It has been postulated that tumor suppressor genes are involved in the cascade of events leading to the toxicity of diverse xenobiotics. Therefore, we have assessed the comparative effects of 0.01, 0.10, and 0.50 median lethal doses (LD(50)) of 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), endrin, naphthalene, and sodium dichromate (VI) [Cr(VI)] on lipid peroxidation, DNA fragmentation, and enhanced production of superoxide anion (cytochrome c reduction) in liver and brain tissues of p53-deficient and standard C57BL/6NTac mice to determine the role of p53 gene in the toxic manifestations produced by these diverse xenobiotics. In general, p53-deficient mice are more susceptible to all four xenobiotics than C57BL/6NTac mice, with dose-dependent effects being observed. Specifically, at a 0.50 LD(50) dose, naphthalene and Cr(VI) induced the greatest toxicity in the liver tissue of mice, and naphthalene and endrin exhibited the greatest effect in the brain tissue. At this dose, TCDD, endrin, naphthalene, and Cr(VI) induced 2.3- to 3.7-fold higher increases in hepatic lipid peroxidation and 1.8- to 3.0-fold higher increases in brain lipid peroxidation in p53-deficient mice than in C57BL/6NTac mice. At a 0. 10 LD(50) dose, TCDD, endrin, naphthalene, and Cr(VI) induced 1.3- to 1.8-fold higher increases in hepatic lipid peroxidation and 1.4- to 1.9-fold higher increases in brain lipid peroxidation in p53-deficient mice than in C57BL/6NTac mice. Similar results were observed with respect to DNA fragmentation and cytochrome c reduction (superoxide anion production). For example, at the 0.10 LD(50) dose, the four xenobiotics induced increases of 1.6- to 3. 0-fold and 1.5- to 2.1-fold in brain and liver DNA fragmentation, respectively, and increases of 1.5- to 2.3-fold and 1.4- to 2.5-fold in brain and liver cytochrome c reduction (superoxide anion production), respectively, in p53-deficient mice compared with control C57BL/6NTac mice. These results suggest that the p53 tumor suppressor gene may play a role in the toxicity of structurally diverse xenobiotics.

Animals↗

PubMed2000

Cadmium- and chromium-induced oxidative stress, DNA damage, and apoptotic cell death in cultured human chronic myelogenous leukemic K562 cells, promyelocytic leukemic HL-60 cells, and normal human peripheral blood mononuclear cells.

Sodium dichromate [Cr(VI)] and cadmium chloride [Cd(II)] are both cytotoxic and mutagenic. This study examined the toxic and apoptotic potentials of these two cations on three cell types in vitro, namely, human chronic myelogenous leukemic (CML) K562 cells, promyelocytic leukemic HL-60 cells, and normal human peripheral blood mononuclear cells. The cells were incubated with 0-100 microM concentrations of the two cations for 0, 24, or 48 hours at 37 degrees C. Both Cr(VI) and Cd(II) induced changes in intracellular oxidized states of cells, which were detected using laser scanning confocal microscopy. Cell cycle modulation and apoptosis of the K562 cells by Cr(VI) and Cd(II) were determined by flow cytometry. Significant decreases in the G2/M phase were observed in the Cr(VI) and Cd(II) treated CML cells compared with untreated cells. At 12.5 microM, Cr(VI) induced greater apoptosis in K562 cells as compared with Cd(II). In the K562 cells, 2.2- and 3.0-fold increases in DNA fragmentation were observed following incubation with 12.5 and 25 microM Cr(VI), respectively, and 1.2- and 1.7-fold increases in DNA fragmentation were observed with Cd(II). Furthermore, approximately 2.7- and 4.9-fold increases in cytochrome c reduction were observed following incubation with 12.5 and 25 microM Cr(VI), respectively, and 1.6- and 3.3-fold increases in cytochrome c reduction were observed with Cd(II), demonstrating enhanced production of superoxide anion. Approximately 3.1 to 6-fold increases in hydroxyl radical production were observed following incubation of the K562 cells with these cations at 12.5 and 25 microM concentrations. These results in K562 cells were compared with promyelocytic leukemic HL-60 cells and normal human peripheral blood mononuclear cells. More pronounced effects were observed on K562 and HL-60 cells, and much lesser effects were observed on normal human peripheral blood mononuclear cells. The results demonstrate that both cations are toxic, producing oxidative tissue damage and apoptosis. Furthermore, more drastic effects were observed on K562 and HL-60 cells as compared with normal human peripheral blood mononuclear cells.

Apoptosis↗

PubMed2000

Oxidative mechanisms in the toxicity of chromium and cadmium ions.

Chromium and cadmium are widely used industrial chemicals. The toxicities associated with both metal ions are well known. However, less information is available concerning the mechanisms of toxicity. The results of in vitro and in vivo studies demonstrate that both cations induce an oxidative stress that results in oxidative deterioration of biological macromolecules. However, different mechanisms are involved in the production of the oxidative stress by chromium and cadmium. Chromium undergoes redox cycling, while cadmium depletes glutathione and protein-bound sulfhydryl groups, resulting in enhanced production of reactive oxygen species such as superoxide ion, hydroxyl radicals, and hydrogen peroxide. These reactive oxygen species result in increased lipid peroxidation, enhanced excretion of urinary lipid metabolites, modulation of intracellular oxidized states, DNA damage, membrane damage, altered gene expression, and apoptosis. Enhanced production of nuclear factor-kappaB and activation of protein kinase C occur. Furthermore, the p53 tumor suppressor gene is involved in the cascade of events associated with the toxicities of these cations. In summary, the results clearly indicate that although different mechanisms lead to the production of reactive oxygen species by chromium and cadmium, similar subsequent mechanisms and types of oxidative tissue damage are involved in the overall toxicities.

Acetaldehyde↗

PubMed2000

Unique organoprotective properties of a novel IH636 grape seed proanthocyanidin extract on cadmium chloride-induced nephrotoxicity, dimethylnitrosamine (DMN)-induced splenotoxicity and mocap-induced neurotoxicity in mice.

Several observations, both in humans and laboratory animals, have suggested that proanthocyanidins exhibit a broad spectrum of pharmacological, therapeutic and chemoprotective properties. Specifically, some of our earlier studies have shown that IH636 grape seed proanthocyanidin extract (GSPE, commercially known as ActiVin) provides excellent concentration- and dose-dependent protection against toxicities induced by diverse agents, such as acetaminophen, hydrogen peroxide, 12-O-tetradecanoylphorbol-13-acetate (TPA), smokeless-tobacco extract, idarubicin and 4-hydroxyperoxycyclophosphamide in both in vitro and in vivo models. In some models, GSPE proved to be a better cytoprotectant than vitamins C, E and beta-carotene. The purpose of this investigation was three fold: (i) to indirectly assess the bioavailability of GSPE in multiple target organs, (ii) quantify GSPE's capacity to avert cadmium chloride (CdCl2)-induced nephrotoxicity, dimethylnitrosamine (DMN)-induced splenotoxicity and O-ethyl-S,S-dipropyl phosphorodithioate (MOCAP)-induced neurotoxicity, and lastly (iii) to evaluate possible mechanisms of protection in mice. In order to determine all these, three separate experiments were designed and each experiment consisted of four groups, such as vehicle control, GSPE alone, toxicant alone and GSPE + toxicant. GSPE was administered orally (100 mg/Kg) for 7-8 days prior to the toxicant exposure. Parameters of the analyses included evaluation of serum chemistry changes (ALT, BUN and CK), histopathology and integrity of genomic DNA, both quantitatively and qualitatively. Results indicate that GSPE preexposure prior to cadmium chloride and DMN provided near complete protection in terms of serum chemistry changes (ALT, BUN and CK) and inhibition of both forms of cell death. e.g., apoptosis and necrosis. DNA damage, a common denominator usually associated with both apoptosis and necrosis was significantly reduced by GSPE treatment. Histopathological examination of organs correlated strongly with the changes in serum chemistry and the DNA modification data. Surprisingly, MOCAP exposure showed symptoms of neurotoxicity coupled with serum chemistry changes in the absence of any significant genomic DNA damage or brain pathology. Although, GSPE appeared to partially protect the neural tissue, it powerfully antagonized MOCAP-induced mortality. Taken together, this study suggests that in vivo GSPE-preexposure may protect multiple target organs from a variety of toxic assaults induced by diverse chemical entities.

Activins↗

PubMed1999

Smokeless tobacco, oxidative stress, apoptosis, and antioxidants in human oral keratinocytes.

We have investigated the effects of a smokeless tobacco extract (STE) on lipid peroxidation, cytochrome c reduction, DNA fragmentation and apoptotic cell death in normal human oral keratinocyte cells, and assessed the protective abilities of selected antioxidants. The cells, isolated and cultured from human oral tissues, were treated with STE (0-300 microl;g/ml) for 24 h. Superoxide anion production was determined by cytochrome c reductase. Oxidative tissue damage was determined by lipid peroxidation and DNA fragmentation, whereas apoptotic cell death was assessed by flow cytometry. STE-induced fragmentation of genomic DNA was also determined by gel electrophoresis. The comparative protective abilities of vitamin C (75 microM), vitamin E (75 microM), a combination of vitamins C & E (75 microM each), and a novel grape seed proanthocyanidin (IH636) extract (GSPE) (100 microg/ml) against STE induced oxidative stress and tissue damage were also determined. Following treatment of the cells with 300 microg STE/ml 1.5-7.6-fold increases in lipid peroxidation, cytochrome c reduction and DNA fragmentation were observed. The addition of the antioxidants to cells treated with STE provided 10-54% decreases in these parameters. Approximately 9, 29, and 35% increases in apoptotic cell death were observed following treatment with 100, 200, and 300 microg STE/ml, respectively, and 51-85% decreases in apoptotic cell death were observed with the antioxidants. The results demonstrate that STE produces oxidative tissue damage and apoptosis, which can be attenuated by antioxidants including vitamin C, vitamin E, a combination of vitamins C plus E and GSPE. GSPE exhibited better protection against STE than vitamins C and E, singly and in combination.

Anthocyanins↗

PubMed1999

Mechanism of gastroprotection by bismuth subsalicylate against chemically induced oxidative stress in cultured human gastric mucosal cells.

Reactive oxygen species (ROS) are implicated in the pathogenesis of chemically induced gastric mucosal injury. We have investigated the effects of ethanol, hydrochloric acid (HCl), and sodium hydroxide (NaOH) on: (1) enhanced production of ROS including superoxide anion and hydroxyl radicals, (2) modulation of intracellular oxidized states by laser scanning confocal microscopy, and (3) DNA fragmentation, indices of oxidative tissue, and DNA damage in a primary culture of normal human gastric mucosal cells (GC), which were isolated and cultured from Helicobacter pylori-negative endoscopic biopsies from human subjects. The induction of ROS and DNA damage in these cells following exposure to ethanol (15%), HCl (150 mM) and NaOH (150 mM) were assessed by cytochrome c reduction (superoxide anion production), HPLC detection for enhanced production of hydroxyl radicals, changes in intracellular oxidized states by laser scanning confocal microscopy, and DNA damage by quantitating DNA fragmentation. Furthermore, the protective ability of bismuth subsalicylate (BSS) was assessed at concentrations of 25, 50, and 100 mg/liter. Incubation of GC with ethanol, HCI, and NaOH increased superoxide anion production by approximately 8.0-, 6.1-and 7.1-fold and increased hydroxyl radical production by 13.3-, 9.6-, and 8.9-fold, respectively, compared to the untreated gastric cells. Incubation of GC with ethanol, HCl, and NaOH increased DNA fragmentation by approximately 6.7-, 4.3-, and 4.8-fold, respectively. Approximately 20.3-, 17.5-, and 13.1-fold increases in fluorescence intensities were observed following incubation of gastric cells with ethanol, HCl, and NaOH, respectively, demonstrating dramatic changes in the intracellular oxidized states of GC following exposure to these necrotizing agents. Preincubation of GC with 25, 50, and 100 mg/liter of BSS decreased ethanol-induced increases in intracellular oxidized states in these cells by 36%, 56%, and 66%, respectively, demonstrating a concentration-dependent protective ability by BSS. Similar results were observed with respect to BSS in terms of superoxide anion and hydroxyl radical production, and DNA damage. The present study demonstrates that ethanol, HCl, and NaOH induce oxidative stress and DNA damage in GC and that BSS can significantly attenuate gastric injury by scavenging these ROS.

Bismuth↗

PubMed1999

Amelioration of the cytotoxic effects of chemotherapeutic agents by grape seed proanthocyanidin extract.

Anticancer chemotherapeutic agents are effective in inhibiting growth of cancer cells in vitro and in vivo, however, toxicity to normal cells is a major problem. In this study, we assessed the effect of a novel IH636 grape seed proanthocyanidin extract (GSPE) to ameliorate chemotherapy-induced toxic effects in cultured Chang epithelial cells, established from nonmalignant human tissue. These cells were treated in vitro with idarubicin (Ida) (30 nM) or 4-hydroxyperoxycyclophosphamide (4HC) (1 microg/ml) with or without GSPE (25 microg/ml). The cells were grown in vitro and the growth rate of the cells was determined using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; thiazolyl blue] assay. Our results showed that GSPE decreased the growth inhibitory and cytotoxic effects of Ida as well as 4HC on Chang epithelial cells in vitro. Because these chemotherapeutic agents are known to induce apoptosis in the target cells, we analyzed the Chang epithelial cells for apoptotic cell population by flow cytometry. There was a significant decrease in the number of cells undergoing apoptosis following treatment with GSPE. We also found increased expression of the anti-apoptotic protein Bcl-2 in GSPE-treated cells using western blot techniques. Thus, these results indicate that GSPE can be a potential candidate to ameliorate the toxic effects associated with chemotherapeutic agents and one of the mechanisms of action of GSPE includes upregulation of Bcl-2 expression.

Anthocyanins↗

PubMed1999

The cytotoxic effects of a novel IH636 grape seed proanthocyanidin extract on cultured human cancer cells.

Grape seed proanthocyanidins are natural antioxidants which possess a broad spectrum of chemoprotective properties against free radicals and oxidative stress. In this study, we have assessed the cytotoxicity of a novel IH636 grape seed proanthocyanidin extract (GSPE) against MCF-7 human breast cancer cells, A-427 human lung cancer cells, CRL-1739 human gastric adenocarcinoma cells and K562 chronic myelogenous leukemic cells at 25 and 50 mg/lit concentrations for 0-72 h using cytomorphology and MTT cytotoxicity assay. In addition, we compared the effects on normal human gastric mucosal cells and normal J774A.1 murine macrophage cells with the effects on the cancer cell lines. Concentration- and time-dependent cytotoxic effects of GSPE were observed on the MCF-7 breast cancer, A-427 lung cancer and gastric adenocarcinoma cells. Following incubation of the MCF-7 cells with 25 mg/lit of the GSPE approximately 6.5, 30 and 43% inhibitions in cell growth were observed at 24, 48 and 72 h of incubation, respectively, while incubation of the MCF-7 cells with 50 mg/lit of the GSPE resulted in 11, 35 and 47% inhibition in cell growth at these same points, respectively. Similar results were observed in the A-427 and gastric adenocarcinoma cells. GSPE exhibited no cytotoxicity toward the neoplastic K562 myelogenous leukemic cells. However, GSPE enhanced the growth and viability of the normal human gastric mucosal cells and J774A.1 murine macrophage cells. These data demonstrate that GSPE exhibited cytotoxicity towards some cancer cells, while enhancing the growth and viability of the normal cells which were examined.

Adenocarcinoma↗

PubMed1999

Acute and chronic stress-induced oxidative gastrointestinal mucosal injury in rats and protection by bismuth subsalicylate.

Reactive oxygen species (ROS) are implicated in the pathogenesis of stress-induced gastrointestinal mucosal injury. In the present study, we have investigated the effects of acute and chronic stress on the enhanced production of ROS including superoxide anion [SA; as determined by cytochrome c reduction (CCR)] and hydroxyl radicals (OH), and correlated the enhanced production of these free radicals with increased lipid peroxidation, membrane microviscosity and DNA fragmentation, indices of oxidative tissue damage, in the gastric and intestinal mucosa of female Sprague-Dawley rats. Furthermore, the protective ability of bismuth subsalicylate (BSS) against the gastrointestinal mucosal injury induced by acute and chronic stress was determined. Acute stress was induced for a period of 90 min, while chronic stress was induced for 15 min/day for 15 consecutive days. Half of the animals exposed to acute stress were pretreated orally with 15 mg BSS/kg 30 min prior to the exposure to acute stress. Similarly, half of the animals exposed to water-immersion restraint chronic stress were pretreated orally with 7.5 mg BSS/kg/day for 15 consecutive days 30 min prior to the exposure to chronic stress. Acute stress produced greater injury to both gastric and intestinal mucosa as compared to chronic stress. Acute stress increased CCR and OH production by 10.0- and 14.3-fold, respectively, in the gastric mucosa, and 10.4- and 17.0-fold, respectively, in the intestinal mucosa. Pretreatment with BSS prevented the acute stress-induced increase in CCR and OH production. Acute stress increased lipid peroxidation, DNA fragmentation and membrane microviscosity by 3.6-, 4.0- and 11.6-fold, respectively, in gastric mucosa, and 4.1-, 5.0- and 16.2-fold, respectively, in intestinal mucosa. BSS decreased acute stress-induced lipid peroxidation, DNA fragmentation and membrane microviscosity by approximately 26, 35 and 30%, respectively, in gastric mucosa, and by 20, 36 and 30%, respectively, in the intestinal mucosa. Chronic stress increased CCR and OH production by 4.8- and 6.3-fold, respectively, in gastric mucosa, and 4.6- and 6.9-fold, respectively, in intestinal mucosa. Chronic stress increased lipid peroxidation and DNA fragmentation by 2.9- and 3.3-fold, respectively, in gastric mucosa, and 3.3- and 4.2-fold, respectively, in intestinal mucosa. BSS decreased chronic stress-induced lipid peroxidation, DNA fragmentation and membrane microviscosity by approximately 41, 44 and 45%, respectively, in gastric mucosa, and by 39, 52 and 51%, respectively, in the intestinal mucosa. Daily administration of BSS provided greater protection against chronic stress-induced oxidative gastrointestinal injury as compared to the acute stress. These results demonstrate that both acute and chronic stress can induce gastrointestinal mucosal injury through enhanced production of ROS, and that BSS can significantly protect against gastrointestinal mucosal injury.

Animals↗