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Biomedical subjects

H Babich

Publications and source records attributed to H Babich.

At least 19 recordsLinked to original sources

In vitro cytotoxicity of a theaflavin mixture from black tea to malignant, immortalized, and normal cells from the human oral cavity.

The growth inhibitory effects of a theaflavin mixture from black tea were more pronounced to malignant (CAL27; HSC-2; HSG1) and immortalized (S-G; GT1) cells than to normal (HGF-2) cells from the human oral cavity. Studies with malignant carcinoma CAL27 cells and immortalized GT1 fibroblasts showed that cytotoxicity of the theaflavin mixture was enhanced as the exposure time was increased, with the tumor CAL27 cells more sensitive than the GT1 cells. Hydrogen peroxide (H(2)O(2)) was detected in cell culture medium amended with the theaflavin mixture. The level of H(2)O(2) in cell culture medium amended with the theaflavin mixture was lessened in the presence of catalase and CoCl(2); the level of authentic H(2)O(2) was also lessened in the presence of CoCl(2), suggesting that Co(2+) led to the rapid catalytic decomposition of H(2)O(2). The cytotoxicity of the theaflavin mixture was due, in part, to the generation in the cell culture medium of H(2)O(2), which lessened the intracellular levels of glutathione in the CAL27 cells and, to a lesser extent, in the GT1 cells. For both cell types, coexposures of the theaflavin mixture with catalase or CoCl(2) afforded protection.

Biflavonoids↗

Mediation of the in vitro cytotoxicity of green and black tea polyphenols by cobalt chloride.

The effects of Co2+ (as CoCl2) on the cytotoxicity of green tea polyphenol (GTP) and black tea polyphenol (BTP) extracts towards proliferation of immortalized human gingival epithelial-like S-G cells were studied. The 24 h potencies of GTP and BTP extracts, as determined with the neutral red (NR) cell viability assay, were greatly reduced in the presence of 250, but not of 50, microM Co2+. The cytotoxicities of the GTP and BTP extracts were due, in part, to their generation of hydrogen peroxide (H2O2) in the cell culture medium (DMEM). Progressively increasing the concentration of Co2+ in the tea polyphenol-amended cell culture medium resulted in a lowering of the level of H2O2. The cytotoxicity of freshly added H2O2 to S-G cells was abolished in the presence of 250 microM Co2+ and the level of freshly added H2O2 to cell culture medium was progressively lowered as the concentration of Co2+ was increased. Apparently, under the conditions of these studies, the decreases in the cytotoxicity of GTP and BTP extracts in the presence of CoCl2 were due to the rapid catalytic decomposition by Co2+ of the H2O2 generated in the tea polyphenol-amended cell culture medium.

Cell Line↗

Differential in vitro cytotoxicity of (-)-epicatechin gallate (ECG) to cancer and normal cells from the human oral cavity.

This study evaluated the biologic activity of epicatechin gallate (ECG), a polyphenol in tea, to carcinoma HSC-2 cells and normal HGF-2 fibroblasts cells from the human oral cavity. The relative cytotoxicity of ECG, as compared to five other polyphenols in tea, was evaluated. For the HSC-2 carcinoma cells, ECG, catechin gallate (CG), and epigallocatechin gallate (EGCG) grouped as highly toxic, epigallocatechin (EGC) as moderately toxic, and catechin (C) and epicatechin (EC) as least toxic. For the HGF-2 fibroblasts, ECG and CG grouped as highly toxic, EGCG as moderately toxic, and EGC, C, and EC as least toxic. The cytotoxic effects of the polyphenols were more pronounced to the carcinoma, than to the normal, cells. The addition of ECG to cell culture medium led to the generation of hydrogen peroxide (H2O2). However, ECG, as compared to EGCG, was a poor generator of H2O2 and, hence, the cytotoxicity of ECG was unaffected by the presence of the antioxidants, N-acetyl cysteine and glutathione, and catalase. The cytotoxicity of ECG was unaffected by a metabolic activating system, i.e., a hepatic microsomal S-9 mix. DNA fragmentation, caspase-3 activity, and nuclear staining, both with acridine orange and the TUNEL procedure, were used to assess ECG-induced apoptosis. ECG induced apoptosis in the carcinoma HSC-2 cells, but not in the normal HGF-2 fibroblasts. This research supports those studies suggesting that tea green is an effective chemopreventive agent of oral carcinoma.

Antioxidants↗

In vitro cytotoxicity to human cells in culture of some phenolics from olive oil.

The neutral red in vitro cytotoxicity assay was used to evaluate the comparative responses of human cells isolated from tissues of the oral cavity to olive oil phenolics. The cell lines used included normal gingival fibroblasts, immortalized, nontumorigenic gingival epithelial cells, and carcinoma cells from the salivary gland. No differences in the relative sensitivities to the phenolics amongst the three cell types were noted. In general, for all cell types, the sequence of increasing cytotoxicity was: oleuropein aglycone>oleuropein glycoside, caffeic acid>o-coumaric acid>cinnamic acid>>tyrosol, syringic acid, protocatechuic acid, vanillic acid. Cytotoxicity was noted only at phenolic concentrations far exceeding those attainable after habitual consumption, thus indicating that consumption of phenol-rich olive oil is safe.

Antineoplastic Agents↗

In vitro cytotoxic and anti-inflammatory effects of myrrh oil on human gingival fibroblasts and epithelial cells.

Limited scientific studies suggest that myrrh (Commiphora molmol) has antibacterial and anti-inflammatory activities. This study determined myrrh oil (MO) cytotoxicity to human gingival fibroblasts and epithelial cells and its effect, measured by ELISA, on interleukin (IL)-1beta-stimulated IL-6 and IL-8 production. Cell viability and cytotoxicity were determined by metabolic reduction of a tetrazolium salt to a formazan dye (MTT assay) and by release of lactate dehydrogenase (LDH) from membrane damaged (LDH release assay) cells, respectively. Based on the MTT assay, 24- and 48-h exposures to </=0.001% MO had little effect on fibroblast and epithelial cell (24-h only) viability. At 48 h, 0.0005-0.001% MO decreased epithelial cell viability 30-50%. After 24 and 48 h, MO, at >/=0.005%, maximally decreased viability of all cell lines. In the LDH release assay, exposure to </=0.0001% MO caused <10% cytotoxicity to all cells. At 24 h, >/=0.0025% MO caused maximal cytotoxicity; </=0.001% MO caused 10-70% cytotoxicity. At longer exposure times, epithelial cells were more susceptible to cytotoxic effects of MO. There was little or no detectable IL-1beta-stimulated production of IL-6 or IL-8 by cells exposed to >/=0.0025% MO, probably reflective of loss of viability. At subtoxic MO levels (0.00001-0.001%), there was a significant reduction of IL-1beta-stimulated IL-6 and IL-8 production by fibroblasts, but not by epithelial cells.

Biological Assay↗

In vitro response of human gingival epithelioid S-G cells to minocycline.

Minocycline, a broad-spectrum antibiotic used in the treatment of acne and periodontal disease and to control inflammatory diseases such as rheumatoid arthritis, has recently been shown to induce a spectrum of adverse health effects. In the light of these contradictory data, this research was directed to provide basic information on the toxicology of minocycline, using in vitro cell culture models, and to evaluate its efficacy in periodontal therapies, particularly for wound healing. The human gingival epithelioid S-G cell line was used as the bioindicator. The greater toxicity of minocycline over doxycycline and tetracycline, related antimicrobial agents, probably correlated with its higher lipophilicity. The cytotoxicity of minocycline was unaffected by an S9 hepatic microsomal fraction, indicating that it is a direct-acting, rather than a metabolism-mediated, cytotoxicant. In comparative toxicity studies, much variation in the degree of sensitivity to minocycline was noted for different cell types. No correlation in the extent of sensitivity to minocycline and the physiologic state of the bioindicator cell (normal, transformed or malignant) was noted. The toxicity of minocycline to the S-G cells was dependent on its concentration and length of exposure. For a continuous 3-day exposure of the S-G cells to minocycline, the midpoint cytotoxicity (or, NR(50)) value, as quantified in the neutral red (NR) assay, was 204 microg/ml on day 1, 84 microg/ml on day 2, and 59 microg/ml on day 3. For a 1-h exposure of the S-G cells in phosphate buffered saline (PBS), the NR(50) value was 780 microg/ml minocycline. Although a 1-h exposure in PBS to 200 microg/ml minocycline exerted some toxicity, the S-G cells recovered on exposure to growth medium; irreversible, progressive damage occurred at 400 microg/ml minocycline and greater. Minocycline, at 50 microg/ml, enhanced attachment of the S-G cells to a gelatin-coated surface and cell migration towards an immobilized fibronectin gradient, both biologic parameters important in periodontal wound healing. Minocycline generally had little or no effect on production of the pro-inflammatory cytokines, interleukin-6 (IL-6) and interleukin-8 (IL-8), by non-activated S-G cells, the exception being stimulation of IL-6 at 48 h. IL-1beta, however, greatly stimulated IL-6 and IL-8 production, which was further increased by concurrent exposure to minocycline. This suggested that minocycline may enhance the ability of gingival epithelial cells to participate in the early, inflammatory phase of periodontal wound healing. The limitation of minocycline efficacy to a rather narrow window of concentration, centering about 50 microg/ml, and primarily for short-term exposures may possibly explain, in part, the contradictory clinical data on the health effects of this drug.

Animal Testing Alternatives↗

In vitro cytotoxicity of glyco-S-nitrosothiols. a novel class of nitric oxide donors.

The cytotoxicities of the nitric oxide (NO) donors, S-nitroso-N-acetylpencillamine (SNAP) and three glyco-SNAPs, glucose-1-SNAP, glucose-2-SNAP, and fructose-1-SNAP, towards the human gingival epithelioid S-G cell line and three human carcinoma cell lines derived from tissues of the oral cavity were compared using the neutral red (NR) assay. In general, the glucose-SNAPs were more cytotoxic than SNAP, which, in turn, was more cytotoxic than fructose-1-SNAP. Further studies focused on the response of S-G cells to glucose-2-SNAP. The cytotoxicity of glucose-2-SNAP was attributed to NO, as glucose-2-SNAP (t1/2=20 h at 28 degrees C) aged for 4 days was nontoxic, toxicity was eliminated in the presence of hydroxocobalamin, a specific NO scavenger, and toxicity was not noted with glucose-2-AP (the parent compound used to construct glucose-2-SNAP). Exposure of cells to glucose-2-SNAP resulted in a lessening of the intracellular level of glutathione and cells pretreated with the glutathione-depleter, 1,3-bis-(chloroethyl)-1-nitrosourea, were more sensitive to a subsequent challenge with glucose-2-SNAP. Cytotoxicity of glucose-2-SNAP was lessened upon coexposure with the antioxidants, myricetin, N-acetyl-L-cysteine, and L-ascorbic acid. S-G cells exposed to glucose-2-SNAP exhibited bi- and multinucleation. Death of S-G cells exposed to glucose-2-SNAP apparently occurred by apoptosis, as demonstrated with fluorescence microscopy by the appearance of brightly stained, hypercondensed chromatin in spherical cells and of membrane blebbing and by the DNA-ladder of oligonucleosome-length fragments noted with gel electrophoresis. In comparison with other classes of NO donors the sequence of toxicity towards S-G cells was S-nitrosoglutathione>glucose-SNAPs>SNAP, sodium nitroprusside>spermine NONOate>DPTA NONOate>DETA NONOate>fructose-1-SNAP>>SIN-1.

Antioxidants↗

In vitro response of human gingival epithelial S-G cells to resveratrol.

WST-1 (mitochondrial dehydrogenase activities). Arrest of cell growth, due to inhibition of DNA synthesis, may explain the leveling of toxicity between day 2 and 3 for a 3-day continuous exposure to resveratrol. Irreversible damage to cell proliferation was noted in S-G cells exposed to 75-150 microM resveratrol for 2 days and then subsequently maintained for another 3 days in resveratrol-free medium. The cytotoxicity of resveratrol was neither potentiated nor ameliorated in the presence of an hepatic S9 microsomal fraction. The cytotoxicity of hydrogen peroxide to S-G cells was lessened by N-acetyl-L-cysteine and quercetin, but not by resveratrol. For nitric oxide, only N-acetyl-L-cysteine reduced toxicity. The ability of resveratrol to function as an antioxidant was, therefore, not noted under these test conditions.

Antineoplastic Agents, Alkylating↗

In vitro cytotoxicity of the nitric oxide donor, S-nitroso-N-acetyl-penicillamine, towards cells from human oral tissue.

The cytotoxicity of the nitric oxide donor, S-nitroso-N-acetyl-penicillamine (SNAP), towards cultured human cells from oral tissue was evaluated. The toxicity of SNAP to Smulow-Glickman gingival epithelial cells was correlated with the liberation of nitric oxide, as N-acetyl-D,L-penicillamine, the SNAP metabolites, N-acetyl-D,L-penicillamine disulfide and nitrite, and preincubated (denitrosylated) SNAP did not affect viability. Comparing equimolar concentrations of various nitric oxide donors, cytotoxicity appeared to be inversely related to the relative stability (i.e., half-life) of the test compound; the sequence of cytotoxicity for a 4 hr exposure was S-nitrosoglutathione>>spermine NONOate> SNAP>DPTA NONOate>>DETA NONOate. Intracellular reduced glutathione (GSH) was lowered in S-G cells exposed to SNAP. Pretreatment of the cells with the GSH depleter, 1,3-bis-(chloroethyl)-1-nitrosourea (BCNU), enhanced the toxicity of SNAP Similar findings of enhanced sensitivity to SNAP were noted with gingival fibroblasts and periodontal ligament cells pretreated with BCNU. The toxicity of SNAP towards the gingival epithelial cells was decreased by cotreatment with the antioxidants, N-acetyl-L-cysteine, L-ascorbic acid, and (+)-catechin. Cells exposed to SNAP exhibited nuclear aberrations, including multilobed nuclei and multinucleation. SNAP-induced cell death was apparently by apoptosis, as noted by fluorescence microscopy and DNA agarose gel electrophoresis.

Cell Line↗

Triclosan: cytotoxicity, mode of action, and induction of apoptosis in human gingival cells in vitro.

The in vitro cytotoxicology of triclosan, the active ingredient in some mouthrinses and dentifrices used in the prevention and treatment of gingivitis and plaque, was studied using the Smulow-Glickman (S-G) human gingival epithelial cell line. The 24 h midpoint cytotoxicity value was 0.05-0.06 mM triclosan as assessed with the neutral red (NR) assay. Triclosan is used in dentifrices in combination with either zinc citrate or sodium fluoride (NaF). The sequence of potencies of these test agents, as assessed with the NR assay, was triclosan>zinc citrate>>NaF; combinations of triclosan + zinc citrate and triclosan + NaF were additive in their toxicities. Damage to the integrity of the plasma membrane, as assessed by the leakage of lactic acid dehydrogenase during a 3-h exposure, was initially evident with 0.1 mM triclosan. When exposed to triclosan for 3 d, a lag in the growth kinetics of the S-G cells was first observed at 0.01 mM triclosan. A reduction in attachment of S-G cells to dentin chips, previously exposed to triclosan for 1 h, was noted at 0.25 mM triclosan and greater. Triclosan-induced cell death was apparently by apoptosis, as noted by fluorescence microscopy and DNA agarose gel electrophoresis of extracted oligonucleosomal fragments.

Anti-Infective Agents, Local↗

Sodium lauryl sulfate and triclosan: in vitro cytotoxicity studies with gingival cells.

Triclosan and sodium lauryl sulfate (SLS) are antimicrobial agents used, both singularly and in combination, in dentifrices and mouth-rinses. Studies by Waaler et al. (Scand. J. Dent. Res. 101 (1993) 192-195) with human volunteers showed that the adverse side-effects induced by SLS in mouth-rinses, i.e. desquamation of oral epithelium and a burning sensation, were lessened by the addition of triclosan. However, Baert et al. (Int. J. Exp. Pathol. 77 (1996) 73-78) showed that triclosan did not protect the hamster cheek pouch mucosa from irritation caused by SLS. The studies presented herein further evaluated, using a cell culture system, the triclosan-SLS interaction. The in vitro cytotoxicities of triclosan and SLS, alone and in combination, were determined with human gingival S-G epithelial cells and GF fibroblasts. The 24-h midpoint (NR50) cytotoxicity values towards the S-G cells were 0.052 mM triclosan and 0.0075% SLS and for the GF fibroblasts the respective values were 0.095 mM triclosan and 0.0127% SLS. Both agents at their NR50 values induced vacuolization. Coexposures of triclosan and SLS were additive in their cytotoxicities towards the S-G epithelial cells and GF fibroblasts. Pretreatment with triclosan potentiated the toxicity of a subsequent exposure of SLS to the S-G cells; a similar pretreatment of the GF fibroblasts with triclosan had no effect on a subsequent challenge with SLS.

Anti-Infective Agents, Local↗

Benzoyl peroxide cytotoxicity evaluated in vitro with the human keratinocyte cell line, RHEK-1.

The human keratinocyte cell line, RHEK-1, was used to evaluate the cytotoxicity of benzoyl peroxide (BZP). As determined with the neutral red (NR) cytotoxicity assay, the 24-h midpoint (NR50) toxicity values, in mM, were 0.11 for BZP and 29.5 for benzoic acid, the stable metabolite of BZP. Irreversible cytotoxicity occurred after a 1-h exposure to 0.15 mM BZP and greater. When exposed to BZP for 7 days, a lag in growth kinetics was first observed at 0.06 mM BZP. Damage to the integrity of the plasma membrane was evident, as leakage of lactic acid dehydrogenase occurred during a 4-h exposure to BZP at 0.05 mM and greater. Intracellular membranes were also affected, as extensive vacuolization, initially perinuclear but then spreading throughout the cytoplasm, was noted in BZP-stressed cells. The generation of reactive free radicals from BZP was suggested by the following: the intracellular content of glutathione was lowered in cells exposed to BZP; cells pretreated with the glutathione-depleting agent, chlorodinitrobenzene, were hypersensitive to a subsequent challenge with BZP; lipid peroxidation by BZP was inducible in the presence of Fe2+; and cells previously maintained in a medium amended with vitamin E, an antioxidant, were more resistant to BZP, showed less lipid peroxidation in the presence of BZP+Fe2+ and did not develop the extensive intracellular vacuolization as compared to non-vitamin E maintained cells.

Benzene Derivatives↗

Cytotoxicity of sanguinarine chloride to cultured human cells from oral tissue.

The in vitro cytotoxicity of sanguinarine chloride, a dental product used in the treatment of gingivitis and plaque, was compared using cell lines and primary cells from oral human tissues. For the established cell lines, sanguinarine chloride exhibited similar potencies to S-G gingival epithelial cells and to KB carcinoma cells, whereas HGF-1 gingival fibroblasts were more tolerant. However, a gingival primary cell culture was more sensitive to sanguinarine chloride than were the established cell lines. Detailed studies were performed with the S-G cells. The 24-hr midpoint (NR50) cytotoxicity value towards the S-G cells was 7.6 microM, based on the neutral red cytotoxicity assay; vacuolization and multinucleation were noted. When exposed to sanguinarine chloride for 3 days, a lag in growth kinetics was first observed at 1.7 microM. Damage to the integrity of the plasma membrane was evident, as leakage of lactic acid dehydrogenase occurred during a 3 hr exposure to sanguinarine chloride at 0.1275 mM and greater. The cytotoxicity of sanguinarine chloride to the S-G cells was lessened in the presence of an S9 hepatic microsomal fraction from Aroclor-induced rats or by including fetal bovine serum (15%) in the exposure medium. Progressively increasing the pH from 6.0 to 7.8 enhanced the potency of sanguinarine chloride, presumably due to the enhanced uptake of the lipophilic alkanolamine form, as compared to that of the cationic iminium form.

Alkaloids↗

An in vitro study on the cytotoxicity of chlorhexidine digluconate to human gingival cells.

Chlorhexidine digluconate is the active ingredient in mouthrinses used to prevent dental plaque and gingivitis. The in vitro cytotoxicity of chlorhexidine was evaluated with the Smulow-Glickman (S-G) gingival epithelial cell line. The potency of chlorhexidine was dependent on the length of exposure and composition of the exposure medium. The midpoint cytotoxicity values for 1-, 24-, and 72-h exposures were 0.106, 0.011, and 0.0045 mmol/L, respectively. S-G cells exposed for 2 h to chlorhexidine and then maintained for 48 h in chlorhexidine-free medium were unable to recover from the initial insult. The adverse effects of chlorhexidine on the plasma membrane were suggested by the leakage of lactic acid dehydrogenase from chlorhexidine-treated S-G cells and by the increased permeability of chlorhexidine-treated liposomes to Ca2+. The toxicity of a 24-h exposure to chlorhexidine to the S-G cells was progressively lessened as the content of fetal bovine serum (FBS) in the exposure medium was increased from 2% to 8%. The potency of a 1-h exposure to chlorhexidine was reduced in medium amended with albumin, lecithin, and heat-killed Escherichia coli. These reductions in toxicity were presumably due to the binding of the cationic chlorhexidine to the negatively charged chemical moieties of the components of FBS and of albumin and lecithin and of sites on the surfaces of bacteria. Combinations of chlorhexidine and carbamide peroxide were additive in their cytotoxicities.

Animals↗

Oxidative stress aspects of the cytotoxicity of carbamide peroxide: in vitro studies.

Carbamide peroxide is the active ingredient in many at-home patient-applied tooth whiteners. The cytotoxicity of carbamide peroxide, as related to oxidative stress, was evaluated in vitro with several human cell lines, including Smulow-Glickman (S-G) gingival epithelial cells. The potency of carbamide peroxide was related to its hydrogen peroxide component rather than to carbamide, was eliminated in the presence of exogenous catalase, and was enhanced in the presence of aminotriazole, an inhibitor of cellular catalase. The intracellular level of glutathione, a scavanger of toxic oxygen metabolites, was decreased in cells exposed to carbamide peroxide; at higher concentrations of carbamide peroxide, leakage of lactic acid dehydrogenase was also evident. Cells pretreated with the glutathione-depleting agents, buthionine sulfoximine, chlorodinitrobenzene, and bis(chloroethyl) nitrosourea, were hypersensitive to subsequent challenge with carbamide peroxide. Conversely, pretreatment with the iron chelator, deferoxamine, protected the cells against subsequent exposure to carbamide peroxide.

Carbamide Peroxide↗

Naphthoquinone cytotoxicity to bluegill sunfish BF-2 cells.

Bluegill sunfish BF-2 fibroblasts were used to evaluate the in vitro cytotoxicities of 1,4-naphthoquinone (NQ), 5,8-dihydroxy-1,4-NQ, and 2,3-dichloro-1, 4-NQ (dichlone); comparisons were made with previously obtained data on the response of human hepatoma HepG2 cells. For both cell types, the sequence of potency was 5,8-dihydroxy-1,4-NQ > 1,4-NQ > dichlone. Dichlone, and, although to a lesser extent, 1,4-NQ and 5,8-dihydroxy-1-4-NQ, induced endoreduplication in the BF-2 cells; for the HepG2 cells, endoreduplication was induced only with dichlone. Exposures to the three NQs reduced intracellular glutathione levels in both cell types. For the BF-2 and HepG2 cells, pretreatments with buthionine sulfoximine (BSO), a glutathione-depleting agent, potentiated the cytotoxicity of 5,8-hydroxy-1,4-NQ and dichlone; pretreatment with dicoumarol, an inhibitor of DT-diaphorase, had no effect on toxicity of these two NQs. Apparently, for these two quinones the predominant metabolic pathway in both the BF-2 and HepG2 cells involved redox cycling via a one-electron reduction reaction, generating reactive oxygen intermediates that consumed intracellular glutathione. Pretreatment of the BF-2 cells with BSO, but not with dicoumarol, potentiated the toxicity of 1,4-NQ, again indicating that metabolism occurred via one electron reduction. However, for the HepG2 cells, pretreatment with dicoumarol, but not with BSO, potentiated the cytotoxicity of 1,4-NQ. Apparently, in the HepG2, as compared to the BF-2, cells, 1,4-NQ was metabolized by DT-diaphorase in a reaction involving a two electron reduction.

Animals↗

Comparative cytotoxicities of selected minor dietary non-nutrients with chemopreventive properties.

The comparative acute cytotoxicities were determined for a varied spectrum of minor dietary non-nutrients that have been implicated as chemopreventive agents. Cytotoxicity was determined with the neutral red (NR) assay, using BALB/c mouse 3T3 fibroblasts as the bioindicators. Based on midpoint cytotoxicity (NR50) values, the range of cytotoxicity for the different chemicals varied by 1000 times. The sequence of potency was tannic acid, tamoxifen citrate, quercetin, benzyl and phenethyl isothiocyanate > glycyrrhetinic acid > indole-3-carbinol > caffeic acid > phytic acid > vanillin > ellagic acid > D-saccharic acid 1,4-lactone. Vanillin, at slight to moderately toxic concentrations, was the only test agent that induced multinucleation in the 3T3 fibroblasts.

3T3 Cells↗

Oxidative stress in fish cells: in vitro studies.

Bluegill sunfish BF-2 fibroblasts were used in the neutral red (NR) cytotoxicity assay to discern the toxicities of hydrogen peroxide (H2O2) and paraquat as indicated by their abilities to induce oxidative stress. The toxicity of H2O2 was markedly enhanced in BF-2 cells treated with the glutathione depleting agents, buthionine sulfoximine (BSO), maleic acid, and chlorodinitrobenzene; similar treatments did not sensitize the BF-2 cells to paraquat, a redox cycling xenobiotic. BSO treated BF-2 cells, however, were sensitized to nitrofurantoin, also a redox cycling chemical. Diethyldithiocarbamate, an inhibitor of superoxide dismutase, only weakly enhanced the sensitivity of the BF-2 cells to H2O2 and paraquat. 1,10-Phenanthroline, a chelator of Fe2+, reduced the cytotoxicity of H2O2 and paraquat, presumably by preventing hydroxyl radical formation in the Fenton reaction. Quin 2 AM, an intracellular chelator of Ca2+, markedly lessened the toxicity of H2O2, but not of paraquat; EGTA, an extracellular chelator of Ca2+, had no effect on the toxicity of H2O2 or paraquat. Apparently, perturbation of intracellular Ca2+ homeostasis is involved in H2O2 toxicity. For comparative purposes, some studies were performed with fathead minnow FHM epithelioid cells, BALB/c mouse 3T3 fibroblasts, and human HepG2 hepatoma cells. The BF-2 fibroblast/NR cytotoxicity red assay was shown to be a suitable model to study oxidative stress in fish.

3T3 Cells↗