OBJECTIVETo investigate the differentiation of bone marrow mesenchymal stem cells (BMSCs) and the effects of BMSCs on the proliferation of cirrhotic fat-storing cells (CFSC) and hepatocytes in vitro.

METHODSBMSCs and hepatocytes were isolated and harvested from the bone marrow and livers of rats. A co-culture system was set up by transwell inserts in which the two chambers were separated by a semipermeable membrane. BMSCs labeled with PKH26 were cultured with hepatocytes/CFSC in the co-culture system and also in a cell-cell direct contact culture system. Anti-albumin and anti-smooth muscle alpha-actin (alpha-SMA) antibodies were tested by using fluorescence immunocytochemistry. BMSCs and hepatocytes/CFSC cultured alone served as controls. The proliferation level of hepatocytes in the co-culture system was measured. CFSC were cultured with the conditional medium of BMSCs, and their quantities were measured microscopically.

RESULTSExpression of albumin was observed in the hepatocytes of the two culture systems after they were cultured for 72 h but the albumin levels were higher in the cell-cell direct contact culture system (P<0.01). As compared to the controls, the number of hepatocytes was larger in the co-culture system (P<0.01). No expression of alpha-SMA in CFSC was observed in either culture system. The proliferation of CFSC was inhibited by the conditional medium of BMSCs. The longer the time of the co-culturing the more significant was the CFSC growth suppression (P<0.01).

CONCLUSIONSBMSCs can be induced into hepatocytes by a local micro-environment formed by hepatocytes. BMSCs may promote proliferation of hepatocytes and inhibit proliferation of CFSC.