Hepatic steatosis prevents heme oxygenase-1 induction by isoflurane in the rat liver

AIM：To characterize the inductive effects of isoflurane（ISO） on hepatic heme oxygenase-1（HO-1） in an animal model of hepatic steatosis.METHODS：Lean（LEAN） and obese（FAT） Zucker rats were randomized into 4 groups：1：LEAN ＋ pentobarbital sodium（PEN）;2：LEAN ＋ ISO;3：FAT ＋ PEN;4：FAT ＋ ISO.The animals were mechanically ventilated for 6 h.In vitro analyses of liver tissue included determination of HO-1 mRNA and protein expression as well as measurement of HO enzyme activity and immunohistochemical analyses.RESULTS：Compared to PEN treatment,ISO administration profoundly induced hepatic HO-1 mRNA and protein expression and significantly increased HO enzyme activity in lean Zucker rats.In contrast,no difference in HO-1 gene expression was observed after ISO or PEN anesthesia in obese Zucker rats.CONCLUSION：The present study demonstrates that ISO is an inducer of hepatic HO-1 gene expression in non-steatotic organs but failed to upregulate HO-1 in steatotic livers.