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PubMed1999

A multi-laboratory evaluation of cryopreserved monkey hepatocyte functions for use in pharmaco-toxicology.

Ethical, economic and technical reasons hinder regular supply of freshly isolated hepatocytes from higher mammals such as monkey for preclinical evaluation of drugs. Hence, we aimed at developing optimal and reproducible protocols to cryopreserve and thaw parenchymal liver cells from this major toxicological species. Before the routine use of these protocols, we validated them through a multi-laboratory study. Dissociation of the whole animal liver resulted in obtaining 1-5 billion parenchymal cells with a viability of about 86%. An appropriate fraction (around 20%) of the freshly isolated cells was immediately set in primary culture and various hepato-specific tests were performed to examine their metabolic, biochemical and toxicological functions as well as their ultrastructural characteristics. The major part of the hepatocytes was frozen and their functionality checked using the same parameters after thawing. The characterization of fresh and thawed monkey hepatocytes demonstrated the maintenance of various hepato-specific functions. Indeed, cryopreserved hepatocytes were able to survive and to function in culture as well as their fresh counterparts. The ability for synthesis (proteins, ATP, GSH) and conjugation and secretion of biliary acids was preserved after deep freeze storage. A better stability of drug metabolizing activities than in rodent hepatocytes was observed in monkey. After thawing, Phase I and Phase II activities (cytochrome P450, ethoxycoumarin-O-deethylase, aldrin epoxidase, epoxide hydrolase, glutathione transferase, glutathione reductase and glutathione peroxidase) were well preserved. The metabolic patterns of several drugs were qualitatively and quantitatively similar before and after cryopreservation. Lastly, cytotoxicity tests suggested that the freezing/thawing steps did not change cell sensitivity to toxic compounds.

Adenosine Triphosphate↗

PubMed2001

Age and gender dependent alterations in the activities of glutathione related enzymes in healthy subjects.

OBJECTIVES: Oxidative stress as a result of increased free radical production is implicated in the pathogenesis of several diseases. Specific antioxidant enzymes have a crucial role in the prevention of these deleterious effects. Since the activities of these enzymes differ significantly in different populations and seem to be affected by various environmental factors, in this study we aimed to determine the reference values of glutathione related antioxidant enzyme activities in the erythrocytes of healthy subjects and to investigate the possible variations as a function of age and gender in a healthy Turkish Mediterranean population. DESIGN AND METHODS: 130 healthy subjects (12-90 yr, 82 females, 48 males) were divided into six different age groups. Erythrocyte glutathione peroxidase (GSH-PX), glutathione reductase (GR) and glutathione-s-transferase (GST) activities were measured on a Hitachi 704 autoanalyser by the modification of previously described manual UV spectrophotometric methods. RESULTS: No significant differences were observed in erythrocyte GSH-PX, GR and GST activities between different age groups. Overall, GST activities were significantly higher in females compared with males (8.08 +/- 1.39, 6.88 +/- 1.51 U/g Hb respectively, mean +/- SD, p < 0.001). A significant positive correlation between GSH-PX and GR activities was observed (r = 0.49, p < 0.001). CONCLUSION: The results of this study suggested that the activities of GSH-PX, GR and GST did not depend. GST activities overall were higher in females. The reference values that we obtained were different than the previous reports. This situation implies that each population should determine its own reference values and should investigate the influence of environmental factors and life style habits on the activities of these enzymes that constitute a major part of the antioxidant defense system in the human organism.

Adolescent↗

PubMed1997

The 58 kDa mouse selenoprotein is a BCNU-sensitive thioredoxin reductase.

The flavoprotein thioredoxin reductase [EC 1.6.4.5] (NADPH + H+ + thioredoxin-S2 --> NADP+ + thioredoxin-(SH)2) was isolated from mouse Ehrlich ascites tumour (EAT) cells. Like the counterpart from human placenta but unlike the known thioredoxin reductases from non-vertebrate organisms, the mouse enzyme was found to contain 1 equivalent of selenium per subunit of 58 kDa. The K(M) values were 4.5 microM for NADPH, 480 microM for DTNB and 36 microM for Escherichia coli thioredoxin, the turnover number with DTNB being approximately 40 s(-1). As mouse is a standard animal model in cancer and malaria research, thioredoxin reductase and glutathione reductase [EC 1.6.4.2] from EAT cells were compared with each other. While both enzymes in their 2-electron reduced form are targets of the cytostatic drug carmustine (BCNU), no immunologic cross-reactivity between the two mouse disulfide reductases was observed.

Animals↗

PubMed1997

Effect of the Host Plant on the Antioxidative Defence in the Midgut of Lymantria dispar L. Caterpillars of Different Population Origins.

THE RESPONSES OF GYPSY MOTH LARVAE ORIGINATING FROM TWO POPULATIONS (OAK FOREST, LOCUST FOREST) TO FAVORABLE (OAK) AND UNFAVORABLE (LOCUST) HOST PLANTS WERE MONITORED AT THE LEVEL OF MIDGUT ANTIOXIDATIVE DEFENCE: the activities of superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), glutathione reductase (GR), glutathione peroxidase like ('GSH-Px like') and glutathione content (GSH). Short-term change of the diet (3 days) to locust leaves of the 5th instar larvae (oak population) provoked an increase in GST and 'GSH-Px like' activities as well as in the amount of GSH. On the contrary, transferring the gypsy moth larvae (locust population) to oak leaves was followed by a decrease in GST, 'GSH-Px like' activities, and in the amount of GSH. Feeding gypsy moth larvae from hatching on an unfavorable host plant such as locust, led to increases in GST and SOD activities and GSH content, as well as to a decrease in CAT activity in all instars studied (4th, 5th, 6th). The locust leaf diet caused changes in other components of antioxidative defence dependent on larval instar and population origin, a feature which could be ascribed to trophic adaptation of the gypsy moth to an unfavorable host plant.

Journal Article↗

PubMed2003

Glutamate loading protects freshly isolated and perfused adult cardiomyocytes against intracellular ROS generation.

Glutamate loading has been shown to protect single isolated perfused cardiomyocytes against metabolic inhibition and wash-off. The mechanism underpinning this protection is unknown. This study aimed to investigate whether reactive oxygen species (ROS) are generated by single isolated perfused cardiomyocytes and whether the protective effect of glutamate loading on cell metabolism is linked to ROS. Single rat cardiomyocytes were isolated with or without glutamate to stimulate glutamate loading. ROS production was measured using 5-(and-6)-chloromethyl-2', 7'-dichlorodihydrofluorescein diacetate in various stressful conditions including metabolic inhibition and wash-off with/without antimycin A or myxothiazol; simulated ischaemia (without cyanide) and glucose reintroduction; and H(2)O(2) perfusion. Reduced glutathione (GSH) levels were measured in control and glutamate-loaded cells with/without exposure to H(2)O(2). Finally, the effect of glutamate on glutathione reductase and glutathione peroxidase activity was measured. In every stressful condition studied, ROS production was significantly lower in glutamate-loaded cells compared to controls. This occurred regardless of whether ROS were produced intracellularly (e.g. from the respiratory chain inhibited with antimycin A) or via the extracellular precursor H(2)O(2). Glutamate-loaded cells also maintained their morphological integrity at higher H(2)O(2) concentrations than control cells. Furthermore, during H(2)O(2) exposure GSH levels decreased in glutamate-loaded cells but stayed constant in control cells. Glutamate stimulated the activity of glutathione peroxidase in a concentration-dependent fashion. These results provide new evidence to show that the cardioprotective effect of glutamate loading may be mediated through an enhanced ability to destroy ROS in the cell.

Animals↗

PubMed2003

Fish tolerance to organophosphate-induced oxidative stress is dependent on the glutathione metabolism and enhanced by N-acetylcysteine.

Dichlorvos (2,2-dichlorovinyl dimethyl phosphate, DDVP) is an organophosphorus (OP) insecticide and acaricide extensively used to treat external parasitic infections of farmed fish. In previous studies we have demonstrated the importance of the glutathione (GSH) metabolism in the resistance of the European eel (Anguilla anguilla L.) to thiocarbamate herbicides. The present work studied the effects of the antioxidant and glutathione pro-drug N-acetyl-L-cysteine (NAC) on the survival of a natural population of A. anguilla exposed to a lethal concentration of dichlorvos, focusing on the glutathione metabolism and the enzyme activities of acetylcholinesterase (AChE) and caspase-3 as biomarkers of neurotoxicity and induction of apoptosis, respectively. Fish pre-treated with NAC (1 mmol kg(-1), i.p.) and exposed to 1.5 mg l(-1) (the 96-h LC85) of dichlorvos for 96 h in a static-renewal system achieved an increase of the GSH content, GSH/GSSG ratio, hepatic glutathione reductase (GR), glutathione S-transferase (GST), glutamate:cysteine ligase (GCL), and gamma-glutamyl transferase (gammaGT) activities, which ameliorated the glutathione loss and oxidation, and enzyme inactivation, caused by the OP pesticide. Although NAC-treated fish presented a higher survival and were two-fold less likely to die within the study period of 96 h, Cox proportional hazard models showed that hepatic GSH/GSSG ratio was the best explanatory variable related to survival. Hence, tolerance to a lethal concentration of dichlorvos can be explained by the individual capacity to maintain and improve the hepatic glutathione redox status. Impairment of the GSH/GSSG ratio can lead to excessive oxidative stress and inhibition of caspase-3-like activity, inducing cell death by necrosis, and, ultimately, resulting in the death of the organism. We therefore propose a reconsideration of the individual effective dose or individual tolerance concept postulated by Gaddum 50 years ago for the log-normal dose-response relationship. In addition, as NAC increased the tolerance to dichlorvos, it could be a potential antidote for OP poisoning, complementary to current treatments.

Acetylcysteine↗

PubMed2000

Effect of singlet oxygen generating substances on the ascorbic acid and glutathione content in pea leaves.

Ascorbate and glutathione levels were investigated in pea leaf discs exposed to various singlet oxygen generating compounds: eosin, rose bengal, monuron, acifluorfen and 5-amino-levulinic acid (ALA). The cellular level of the major antioxidant ascorbate was markedly decreased by the herbicides monuron, acifluorfen and ALA (in light-dependent reactions), as well as by the xanthene dyes eosin and rose bengal (independently of light). No significant accumulation of dehydroascorbate could be observed in any treatments. In contrast to ascorbate, the foliar glutathione levels were considerably increased by subtoxic or slightly toxic concentrations of eosin, rose bengal, acifluorfen and ALA in a light-dependent manner. Monuron treatments led to unchanged or decreasing glutathione contents. The activities of three antioxidative enzymes (ascorbate peroxidase, glutathione reductase and glutathione S-transferase) were also induced by eosin in light-dependent reactions.

Journal Article↗

PubMed1998

Attenuation of iron-nitrilotriacetate (Fe-NTA)-mediated renal oxidative stress, toxicity and hyperproliferative response by the prophylactic treatment of rats with garlic oil.

Iron nitrilotriacetate (Fe-NTA) is a potent nephrotoxic agent. In this communication we show that Fe-NTA-mediated nephrotoxicity is diminished by 1 wk of oral daily pretreatment of male albino Wistar rats with garlic oil given by gavage at 50 or 100 mg/kg body weight/ml corn oil. Intraperitoneal Fe-NTA treatment at a dose level of 9 mg Fe/kg body weight/10 ml enhances renal microsomal lipid peroxidation and hydrogen peroxide generation which are accompanied by a decrease in the activities of renal antioxidant enzymes (e.g. catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase), and a depletion in the level of renal glutathione. Parallel to these changes, a sharp increase in blood urea nitrogen and serum creatinine has been observed. In addition, Fe-NTA treatment also enhances renal ornithine decarboxylase (ODC) activity and increases [3H]thymidine incorporation into renal DNA. Prophylactic treatment of animals with garlic oil before the administration of Fe-NTA resulted in the diminution of Fe-NTA mediated injury. The enhancement of renal lipid peroxidation and hydrogen peroxide generation was decreased. In addition, there was recovery of glutathione depletion and inhibition of the activities of antioxidant enzymes. Similarly, in animals given the higher dose of garlic oil (100 mg/kg body weight) the enhanced blood urea nitrogen and serum creatinine levels, which are indicative of renal injury, showed a reduction of about 30% and 40%, respectively, in comparison with the group treated with Fe-NTA alone. Pretreatment with garlic oil also ameliorated the Fe-NTA-mediated induction of ODC activity and enhancement of [3H]thymidine incorporation into DNA in a dose-dependent manner. Our data suggest that garlic oil is a potent chemopreventive agent and may suppress Fe-NTA-induced nephrotoxicity.

Administration, Oral↗

PubMed2003

Palm oil alleviates 12-O-tetradecanoyl-phorbol-13-acetate-induced tumor promotion response in murine skin.

Palm oil is a rich source of vitamin E, carotenoids, tocotrienols and tocopherols which are natural antioxidants and act as scavengers of oxygen free radicals. 12-O-Tetradecanoyl-phorbol-13-acetate (TPA) is a known oxidant that promotes tumorigenesis in mouse skin through the elaboration of oxidative stress. In this study we therefore assessed the anti-tumor promoting potential of palm oil against TPA-mediated skin tumorigenesis in 7,12-dimethylbenz[a]anthracene-initiated Swiss albino mice. Topical application of palm oil 1 h prior to application of TPA resulted in a significant protection against skin tumor promotion. The animals pre-treated with palm oil showed a decrease in both tumor incidence and tumor yield as compared to the TPA (alone)-treated group. Palm oil application also reduced the development of malignant tumors. Since TPA-induced epidermal ornithine decarboxylase (ODC) activity and [(3)H]thymidine incorporation are conventionally used markers of skin tumor promotion, we also assessed the effect of pre-application of palm oil on these parameters, and it was observed that the application of palm oil prior to the application of TPA alleviated both these TPA-induced markers of tumor promotion. The effect of pre-application of palm oil on TPA-mediated depletion in the non-enzymatic and enzymatic molecules was also assessed and it was observed that palm oil application prior to TPA application resulted in the recovery of TPA-mediated depletion in the levels of these molecules viz. glutathione, glutathione peroxidase, glutathione reductase, glutathione-S-transferase and catalase. Similarly, palm oil also exhibited a protective effect against Fe(2+)-ascorbate-induced lipid peroxidation in the epidermal microsomes. The results of the present study thus suggest that palm oil possesses anti-skin tumor promoting effects, and that the mechanism of such effects may involve the inhibition of tumor promoter-induced epidermal ODC activity, [(3)H]thymidine incorporation and cutaneous oxidative stress.

Administration, Topical↗

PubMed2002

Procyanidins protect Fao cells against hydrogen peroxide-induced oxidative stress.

In this paper, we evaluate the extent to which flavonoids in red wine (catechin, epicatechin, quercetin and procyanidins) protect against hydrogen peroxide-induced oxidative stress in Fao cells. When cells were exposed to H(2)O(2), malondialdehyde (MDA) levels, oxidized glutathione (GSSG) levels and lactate dehydrogenase (LDH) release increased, indicating membrane damage and oxidative stress. All the flavonoids studied, and in particular epicatechin and quercetin, protected the plasma membrane. Only procyanidins lowered MDA levels and LDH leakage, maintained a higher reduced/oxidized glutathione ratio, and increased catalase/superoxide dismutase and glutathione peroxidase/superoxide dismutase ratios, and glutathione reductase and glutathione transferase activities. These results show that the procyanidin mixture has a greater antioxidant effect than the individual flavonoids studied, probably due to its oligomer content and/or the additive/synergistic effect of its compounds. This suggests that the mixture of flavonoids found in wine has a greater effect than individual phenols, which may explain many of the healthy effects attributed to wine.

Antioxidants↗

PubMed2003

Novel B melatonin-loaded chitosan microcapsules: in vitro characterization and antiapoptosis efficacy for aflatoxin B1-induced apoptosis in rat liver.

The aim of this study was to prepare buoyant (B) melatonin (MT)-loaded chitosan microcapsules having favourable sustained release characteristics (in simulated gastric fluid (SGF), pH 1.2) in comparison with non-buoyant (NB) chitosan particles. The new buoyant microcapsules were prepared by the ionotropic gelation method using sodium lauryl sulfate (NaLS) for coagulation. The microcapsule characteristics were affected by the initial drug and NaLS concentrations, as well as the presence of sodium dioctyl sulfosuccinate (DOS) or pectin with NaLS in the external phase. In general, spherical microcapsules with 36.90-56.23% encapsulation efficiencies, hollow core and satisfactory release properties were produced. The best sustained release profiles (t(50%): 5h) with near zero-order kinetics were observed with the higher theoretical payload microcapsules prepared with both NaLS and DOS in a 1:2 ratio. In vivo studies were also carried out to exploit the protective effect of the MT-loaded NaLS-DOS microcapsules against aflatoxin B1 (AFB1)-induced toxicity (liver apoptosis) in male rats. The results implied that apoptotic rate was significantly reduced when MT or its microcapsules formulation was co-administered with AFB1. The levels of the oxidative stress indices (malondialdehyde (MDA), a lipid peroxidation product and nitric oxide (NO)) in liver tissues were significantly reduced, while the levels of the hepatic antioxidants (glutathione (GSH) and zinc (Zn), as well as the enzyme activities of glutathione reductase (GR), glutathione peroxidase (GSPx) and glutathione-S-transferase (GST)) which act as antiapoptosis were significantly increased as compared to AFB1 group (without MT). MT microcapsules appeared more effective in reduction of apoptotic rate than free MT as indicated by the decline of caspase-3 activities (an apoptotic marker) and confirmed by histopathology.

Administration, Oral↗

PubMed2001

Carboplatin-induced oxidative stress in rat cochlea.

Carboplatin is currently being used in the clinic against a variety of human cancers. However, high dose carboplatin chemotherapy resulted in ototoxicity in cancer patients. This is the first study to show carboplatin-induced oxidative stress response in the cochlea of rat. Male Wistar rats were divided into two groups of six animals each and treated as follows: (1) control (normal saline, i.p.) and (2) carboplatin (256 mg/kg, i.p.). Animals in both groups were sedated with ketamine/xylazine and auditory brainstem-evoked responses were recorded before and 4 days after treatments. The animals were sacrificed on the fourth day and cochleae were harvested and analyzed. A significant elevation of the hearing threshold shifts was noted at clicks, 8, 16, and 32 kHz tone burst stimuli following carboplatin administration. Carboplatin significantly increased nitric oxide and malondialdehyde levels, xanthine oxidase and manganese-superoxide dismutase activities in the cochlea indicating enhanced flux of free radicals. Cochlear glutathione levels, antioxidant enzyme activities such as copper zinc-superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase and enzyme protein levels were significantly depleted 4 days after carboplatin treatment. The data suggest that carboplatin induced free radical generation and antioxidant depletion, and caused oxidative injury in the cochleae of rats.

Animals↗

PubMed2000

Antihepatotoxic activity of bergenin, the major constituent of Mallotus japonicus, on carbon tetrachloride-intoxicated hepatocytes.

To determine the antihepatotoxic activity of bergenin from Mallotus japonicus, carbon tetrachloride (CCl4)-induced cytotoxicity in primary cultured rat hepatocytes has been adopted as an assay system. Bergenin significantly reduced the activities of glutamic pyruvic transaminase and sorbitol dehydrogenase released from the CCl4-intoxicated hepatocytes. The antihepatotoxicity of bergenin was also evidenced by elevating the activities of glutathione S-transferase and glutathione reductase, and content of glutathione in the CCl4-intoxicated hepatocytes. From these results, it is assumed that bergenin exerted antihepatotoxicity against CCl4-induced cytotoxicity through glutathione-mediated detoxification as well as free radical suppressing activity.

Alanine Transaminase↗

PubMed2003

The antioxidant status during maturation of reticulocytes to erythrocytes in type 2 diabetics.

Free radical-induced lipid peroxidation has been associated with numerous disease processes including diabetes mellitus. The extent of lipid peroxidation (LPO) and antioxidant defense system [i.e., levels of glutathione (GSH), glucose-6-phosphate dehydrogenase (G6PDH), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione-S-transferase (GST), and catalase (CAT)] were evaluated in reticulocytes and erythrocytes of type 2 diabetic males and age-matched controls. Type 2 diabetics have shown increased lipid peroxidation and decreased levels of GSH, GR, GPx, G6PDH, and GST both in reticulocytes and erythrocytes compared to controls, indicating the presence of oxidative stress and defective antioxidant systems in these patients. CAT activity is found to be enhanced in both the reticulocytes and erythrocytes of diabetics, with a greater percentage enhancement in reticulocytes. The extent of increase in lipid peroxidation is greater in erythrocytes compared to reticulocytes in these patients. Furthermore, the maturation of reticulocytes to erythrocytes resulted in decreased GSH and decreased activities of all antioxidant enzymes (except CAT) both in normals and type 2 diabetes individuals, indicating decreased scavenging capacity as reticulocytes mature to erythrocytes. These maturational alterations are further intensified in type 2 diabetics. The present study reveals that the alterations in lipid peroxidation and antioxidant system lean toward early senescence of erythrocytes in type 2 diabetic patients.

Adult↗

PubMed2002

Free radicals, antioxidants, and nutrition.

Radiation hazards in outer space present an enormous challenge for the biological safety of astronauts. A deleterious effect of radiation is the production of reactive oxygen species, which result in damage to biomolecules (e.g., lipid, protein, amino acids, and DNA). Understanding free radical biology is necessary for designing an optimal nutritional countermeasure against space radiation-induced cytotoxicity. Free radicals (e.g., superoxide, nitric oxide, and hydroxyl radicals) and other reactive species (e.g., hydrogen peroxide, peroxynitrite, and hypochlorous acid) are produced in the body, primarily as a result of aerobic metabolism. Antioxidants (e.g., glutathione, arginine, citrulline, taurine, creatine, selenium, zinc, vitamin E, vitamin C, vitamin A, and tea polyphenols) and antioxidant enzymes (e.g., superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidases) exert synergistic actions in scavenging free radicals. There has been growing evidence over the past three decades showing that malnutrition (e.g., dietary deficiencies of protein, selenium, and zinc) or excess of certain nutrients (e.g., iron and vitamin C) gives rise to the oxidation of biomolecules and cell injury. A large body of the literature supports the notion that dietary antioxidants are useful radioprotectors and play an important role in preventing many human diseases (e.g., cancer, atherosclerosis, stroke, rheumatoid arthritis, neurodegeneration, and diabetes). The knowledge of enzymatic and non-enzymatic oxidative defense mechanisms will serve as a guiding principle for establishing the most effective nutrition support to ensure the biological safety of manned space missions.

Antioxidants↗

PubMed2001

Melatonin reduces oxidative stress induced by ochratoxin A in rat liver and kidney.

Melatonin (MEL) displays antioxidant and free radical scavenger properties. In the present study, the effect of MEL on the oxidative stress induced by ochratoxin A (OTA) administration in rats was investigated. Four groups of 15 rats each were used: controls, MEL-treated rats (5 mg/kg body mass), OTA-treated rats (250 microg/kg) and MEL+OTA-treated rats. After 4 weeks of treatment, the levels of malondialdehyde (MDA), a lipid peroxidation product (LPO) were measured in serum and homogenates of liver and kidney. Also, the levels of glutathione (GSH), and activities of glutathione reductase (GR), glutathione peroxidase (GSPx), superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) in liver and kidney were determined. In OTA-treated rats, the levels of LPO in serum and in both liver and kidney were significantly increased compared to levels in controls. Concomitantly, the levels of GSH and enzyme activities of SOD, CAT, GSPx and GR in both liver and kidney were significantly decreased in comparison with controls. In rats received MEL+OTA, the changes in the levels of LPO in serum and in liver and kidney were not statistically significant compared to controls. Concomitantly, the levels of GSPx, GR and GST activities in both liver and kidney tissues were significantly increased in comparison with controls. Similar increases in GSPx, GR and GST activities were also observed in MEL-treated rats when compared with controls. In conclusion, the oxidative stress may be a major mechanism for the toxicity of OTA. MEL has a protective effect against OTA toxicity through an inhibition of the oxidative damage and stimulation of GST activities. Thus, clinical application of melatonin as therapy should be considered in cases of ochratoxicosis.

Animals↗

PubMed2003

Xenobiotic conjugation systems in deer compared with cattle and rat.

The ability of cattle and deer liver to catalyse xenobiotic conjugation reactions was investigated and compared with that of the rat. Marked differences in the activity of these enzymes were noted between the domestic animals and rats. Hepatic microsomal epoxide hydrolase activity in cattle and deer, determined using benzo[a]pyrene 4,5-oxide as substrate, was nearly twice that of the rat. In contrast, glutathione S-transferase activity in hepatic cytosol, determined with 1-chloro-2,4-dinitrobenzene as substrate, was significantly lower in the cattle and deer. When 1,2-dichloro-4-nitrobenzene served as the accepting substrate, no activity was detectable in the cattle and deer. Similarly, glutathione reductase activity and total glutathione levels were markedly lower in the cattle and deer compared with the rat. Cytosolic sulfotransferase activity, monitored using 2-naphthol as substrate, was higher in cattle compared with the rat. Finally, microsomal UDP-glucuronosyl transferase activity, determined using 1-napththol as substrate, did not differ significantly among the three species.

Animals↗

PubMed2003

Protective effects of fermented filtrate from Antrodia camphorata in submerged culture against CCl4-induced hepatic toxicity in rats.

The protective effects and the possible mechanisms of dry matter of fermented filtrate (DMF) from Antrodia camphorata in submerged culture (ACSC) on H(2)O(2)-induced cytotoxicity in HepG2 and carbon tetrachloride (CCl(4))-induced hepatotoxicity in Sprague-Dawley rats were investigated. The results showed that the inhibitory effect of DMF and its crude triterpenoids on lipid peroxidation occurred in a dose-response manner in an AAPH/linoleic acid system. When HepG2 cells were pretreated with DMF at the concentration of 0.10 mg/mL for 4 h and then induced by 1 h of treatment with H(2)O(2) (100 microM), lipid peroxidation was significantly (p < 0.05) decreased, as measured by the formation of malondialdehyde. The oral pretreatment with DMF [0.25 and 0.50 mg/kg of body weight (bw)] for 5 consecutive days prior to the administration of a single dose of 40% CCl(4) (0.10 mL/100 g of bw, ip) significantly prevented the increase in serum levels of hepatic enzyme markers (alanine and aspartate aminotransferase) and liver lipid peroxidation (p < 0.05). Histopathological evaluation of the rat liver revealed that DMF reduced the incidence of liver lesions, including neutrophil infiltration, hydropic swelling, and necrosis induced by CCl(4) in rats. Moreover, reduced glutathione (GSH)-dependent enzymes (glutathione peroxidase, glutathione reductase, and glutathione S-transferase) and the GSH/GSSG ratio were significantly improved in the oral pretreatment DMF of rats (p < 0.01). The results suggest that DMF may play a role in preventing oxidative damage in living systems by up-regulating hepatic GSH-dependent enzymes to preserve the normal GSH/GSSH ratio and scavenging free radicals formed during CCl(4) metabolism.

Animals↗