大鼠肝移植自然耐受模型移植术后Foxp3基因表达的变化

Foxp3 gene expression in rat allograft liver transplantation tolerance model

目的探讨大鼠肝移植自然耐受模型移植术后Foxp3基因表达的变化及意义。方法分别建立大鼠急性排斥（DA→LEW）、自然耐受（LEW→DA）、同基因组（DA→DA）肝移植模型，收集术后7、14、28d外周血、脾脏、肝脏标本，FCM检测标本淋巴细胞中CIN^＋CD25^＋Tr（regulatoryTcell）比例变化，RT-PCR，Westernblot分别检测肝脏内Foxp3基因及其scrufin蛋白的表达。结果术后7d，各组外周血、脾脏、肝脏中CD4^＋CD25^＋Tr细胞比例无明显差异。术后14d自然耐受组脾脏、肝脏内CD4^＋CD25^＋Tr细胞比例明显高于同基因组（P〈0．05），外周血中差异无统计学意义（P〉0．05）。术后28d自然耐受组与同基因组间无差异（P〉0．05）。术后7d，自然耐受组移植物Foxp3mRNA水平明显高于排斥组和同基因组（P〈0．05）；术后14d，自然耐受组移植物Foxp3mRNA水平明显高于同基因组（P〈0．05）；术后28d，自然耐受组与同基因组移植物Foxp3mRNA表达无差异（P〉0．05）。自然耐受组与同基因术后14、28d scrufin蛋白条带明显强于7d，且自然耐受组表达强于同基因组。结论大鼠肝移植术后1～2周内，移植肝内Foxp3基因表达可诱导机体对移植物产生免疫耐受。

Objective To investigate the expression of Foxp3 gene and the significance of the change in the tolerance model of rat allograft liver transplantation. Methods After rat models of tolerance and isogenic liver transplantation were established, blood, spleen and graft samples from each group were collected on the 7th, 14th and 28th post-transplantation day. The ratio of CD4^＋ CD25^＋ T cells in the PBMC separating from blood, spleen and graft was compared. The expression of Foxp3 gene in the graft was detected by real time PCR,and that of scrufin protein of graft by Western blot in each group. Results The ratios of CD4^＋ CD25^＋ T cell in spleen and graft of tolerance group were higher than those in isogenic group on the 14th post-transplantation day（P〈0.05）, which were not significantly different among three groups on the 7th day（P〉0.05）. The Foxp3 gene expression in grafts of tolerance group was higher than that in the other two groups on the 7th day （P〈0.05）, which was higher than that in isogenic group on the 14th day（P〈0.05）. The graft scrufin levels in isogenic and tolerance group on the 14th and 28th day were both higher than those on the 7th day, and the graft scrufin level was higher in tolerance group than that in isogenic group in both phases. Conclusion Foxp3 gene expression in liver graft plays an important role in the tolerance induction within 1 to 2 weeks after transplantaiton.