Abstract: Abstract Objective: To investigate the effects of rat bone marrow mesenchymal stem cells on liver regeneration and repair after 80% hepatectomy. Methods: BMSCs were isolated and purified by adherent method, identified by surface markers via flow cytometry. 36 rats model of 80% hepatectomy were randomized into 2 groups: experimental group contains 16 rats with BMSC injection via their portal veins and control group contains 20 rats with saline by the same way. Using biochemical methods to test liver function, the flow cytometry and immunohistochemistry to detect cell cycle and proliferation cell nuclear antigens. Results: ① We isolated, cultured and proliferated BMSCs successfully in vitro. ② Survival rate after operation: survival rate was 93.7% in the experimental group and 75% in control group. ③ Liver tissue display that the hepatocyte necrosis and inflammatory cells proliferation and cellular edema, ballooning degeneration markedly reduced significantly in experimental group compared with the control group. ④ 1std, 3th d, 7th d after operation, the levels of ALT and AST recover significantly in experimental group than in the control group, the difference was statistically significant (P <0.05). ⑤ The S phase of cell cycle was significantly higher in experimental group than in the control group (P <0.05). ⑥ Remnant liver immunohistochemistry showed that PCNA expression was significantly higher in the experimental group than in the control group (P <0.05). Conclusion: BMSCs can improve significantly rat liver regeneration and repairment after 80% hepatectomy.

Key words: bone marrow mesenchymal stem cells, hepatectomy, rat, regeneration, repair