AIM: To study the effect of retrorsine on mouse hepatocyte proliferation.METHODS: Mice and rats were treated respectively with two injections of retrorsine (as retrosine-treated group) or saline (as non-treated group) at 2 wk intervals.They received a single injection of carbon tetrachloride (CCl4) 4 wk later. On d 0, 1, 2, 3, 4, 6, 15 after CCl4 administration, the animals were killed and their livers were excised. Hematoxylin and eosin (HE) staining and Ki-67 antibody immunohistochemical analysis of liver samples were used to evaluate the pathological changes and hepatocyte proliferation.RESULTS: In rats treated with retrorsine and CCl4, the liver displayed obvious megalocytosis, proliferation of mild bile duct, small hepatocyte-forming nodule, which were not found in liver samples from non-treated group.However, in mice treated with retrorsine combined with CCl4, the liver displayed hepatocyte degeneration and necrosis in perivenous areas. There was no obvious difference between retrorsine-treated group and nontreated group. Ki-67 immunohistochemical analysis showed that in rats treated with retrorsine, the positive hepatocytes mainly found in small hepatocyte nodules,were obviously less than those in non-treated group. The mice treated with retrorsine showed that the number of Ki-67 positive hepatocytes was very high and more than that in non-treated group.CONCLUSION: Retrorsine has no effect on mouse hepatocyte proliferation.