摘要BACKGROUND:Many studies have shown that bone marrow mesenchymal stem cel s could improve liver fibrosis.OBJECTIVE:To observe the effect of bone marrow mesenchymal stem cel s on fibrosis in chronic hepatic injury induced by diethylnitrosamine.METHODS:Twenty female Wistar rats were used to establish the model with chronic hepatic injury induced by diethylnitrosamine, and then the models were randomly divided into two groups. Rats in the mesenchymal stem cel s group (n=10) received 1×106/mL male bone marrow mesenchymal stem cel s injection through caudal vein at 4,8,12 andRESULTS AND CONCLUSION:At 20 weeks after chronic hepatic injury, sex-determining region of Y-chromosome was detected in mesenchymal stem cel s group but not in model group. It indicated that bone marrow mesenchymal stem cel s were successful y transplanted in mesenchymal stem cel s group, and survived. MRI showed that a large number ofregenerative nodules could be seen in mesenchymal stem cel s group. Comparred with model group, the number ofregenerative nodules, fibrosis score,α-smooth muscle actin and percentage of col agen area were increased inmesenchymal stem cel s group (P<0.05). Under our experimental conditions, bone marrow mesenchymal stem cel s in systemic circulation leads to their engraftment into liver tissue and promotes fibrosis in rat model of severe chronic liver injury induced by diethylnitrosamine.16 weeks, and the rats in the model group received equal volume of saline injection.