Study on the inhibitive effect of mesenchymal stem cells on the immunological rejection in rats after liver transplantation.

Objective To investigate the inhibitive effect of mesenchymal stem cells (MSCs) on the immunological rejection in rats after liver transplantation. Methods The recipients and donors were female SD rats and Wistar rats. All rats were randomly divided into 3 groups (28 rats in each group). Rats in group A were infused with normal saline; rats in group B received FK506 (0.25 mg/kg) every 2 days for 2 weeks after liver transplantation; rats in group C were injected with MSCs from male Wistar rats during liver transplantation. The pathological changes, expression of TGF-β1 and IL-10, Y chromosome location, changes of liver function and the survival of the recipients were detected on postoperative day 10. The levels of ALT and AST were analyzed by com-pletely randomised design analysis of variance, and the difference among the 3 groups were analyzed by LSD. Ridit was used to analyze the pathological grading. The survival was analyzed by Log-rank test after the Kaplan-Meier survival curve was drawn. Results The values of ALT and AST were (756±104)U/L and (635±134)U/L in group A, (197±49)U/L and (331±78) U/L in group B, (103±31)U/L and (150±38) U/L in group C, respectively. The difference in the level of ALT and AST among the 3 groups had statistical significance (F = 158, 265, P < 0.05). The liver function of rats in group B and C was better than those in group A (P < 0.01), and the liver function of rats in group C was better than those in group B. The mean values of ridit in group A, B and C were 0.8333, 0.4583 and 0.2083, respectively. The expression rates of TCG-β1 in group A, B and C were 18%±5% , 69%±20% and 85%±24% , with statistical difference among the 3 groups (F=191, P <0.01). There was a significant difference in IL-10 expression among group A (21%±5%), group B (75%±14%) and group C (91%±21%) (F=672, P<0.01). The TCG-β1 and IL-10 had strong positive expression in group B and C, and the expression of TCG-β1 and IL-10 was much stronger in group C than in group B; while the expres-sion of TCG-β1 and IL-10 was weak positive in group A. MSCs cells with Y chromosome were positively stained and were concentrated at the portal area in group C. The 50-day survival rate of rats in group A, B and C were 0, 10% and 90% , respectviely, with significant difference (χ~2=36, P < 0.01). The median survival time of rats in group C was 63 days, which was longer than that in group A and B. Conclusion Simultaneous injection of MSCs from donors during liver transplantation can inhibite the immunological rejection of recipients to the liver graft. Key words: Mesenchymal stem cells;  Liver transplantation;  Immunological rejection