S-adenosyl-L-methionine attenuates hepatotoxicity induced by agonistic Jo2 fas antibody following CYP2E1 induction in mice

S- Adenosyl- L- methionine ( SAM) has been shown to be hepa-toprotective against many toxic agents. Its possible effectiveness in protecting against CYP2E1- dependent toxicity is not known. We recently reported that treatment of mice with pyrazole to induce CYP2E1 increased hepatotoxicity produced by Fas agonistic Jo2 antibody. The current study was designed to investigate the effect of exogenous administration of SAM on the synergistic hepatotoxicity produced by Fas agonistic Jo2 antibody plus CYP2E1 following pyrazole pretreatment in C57BL/ 6 mice. Suboptimal administration of Jo2 Fas antibody combined with pyrazole pretreatment caused severe hepatotoxicity as determined by elevations in serum transaminase levels and histopathology. Exogenous administration of SAM ( 50 mg i. p./ kg body weight every 12 h for 3 days) significantly decreased serum transaminases and ameliorated morphological changes of the liver. Addition of SAM elevated hepatic SAM and total reduced glutathione levels and inhibited CYP2E1 activity. SAM also lowered the elevated oxidative stress ( lipid peroxidation, protein carbonyls, and superoxide production) and nitrosative stress ( induction of inducible nitric- oxide synthase and 3- nitrotyrosine adducts) and increases in caspase- 8 and - 3 activation produced by the pyrazole plus Jo2 treatment. SAM did not prevent the increase in serum TNF- alpha levels or the decrease in catalase activity in this model. These results indicate that SAM can have an important hepatoprotective role as an effective reagent against Fas plus CYP2E1- induced hepatotoxicity by lowering oxidative and nitrosative stress.