转Fas配体基因的树突状细胞在诱导大鼠肝移植免疫耐受中的作用

目的 探讨受者体内注射转FasL基因垢树突状细胞（DC）诱导大鼠肝移植免疫耐受的作用机制。方法 建立SD大鼠→Wistar大鼠肝移植模型。分别于术前5d给受者腹腔注射转染多药耐药基因（mdr1)的DC细胞或转染FasL基因的DC细胞,并设空白对照组和环孢素A（CsA)对照组。术后3d和7d测定移植肝功能,册时以半定量逆转录聚合酶链反应（RT-PCR）检测移植肝组织中Fas,Fas配体（FasL)及白细胞介素12（IL-12）,并观察受鼠的存活时间。结果 空白对照组的大鼠术后9-15d全部死亡,CsA治疗组及转FasL基因治疗组;空白对照组及转mdr1基因治疗组的FasL及IL-12表达增高,而CsA治疗组及转FasL基因治疗组的FasL及IL-12呈不表达或低表达。结论 转染FasL基因的DC细胞能有效地诱导大鼠肝移植免疫耐受,其机理可能与诱导了肝脏内浸润淋巴细胞凋亡及抑制IL-2的表达有关。

Mechanism of tolerance inducement in rat liver transplantation by constructing retroviral vector containing FasL gene

Objective To explore the further mechanism of immune tolerance induced by injecting dendritic cells transfected with FasL gene in rat liver transplantation. Methods Orthotopic liver transplantation models in 36 Wistar rats receiving SD liver as donors were established by using "the two cuff technique" with some modifications. The rats were randomly divided into 3 groups: CsA treated group ( n =12) treated with cyclosporine; mdrl treated group ( n =12) treated with dendritic cells transfected with mdr1 gene and FasL group ( n =12) treated with the dendritic cells transfected with FasL gene by intraperitoneal injection. 12 normal Wistar rats served as control group. Four rats in each group were killed on the postoperative day(POD)7 respectively. The liver and peripheral blood were obtained to determine liver function, mRNA expression of Fas, FasL, IL 12 in the grafts by semi quantitative RT PCR. Results It was found that the rats in the control group all died between 9 15 days after operation, and the levels of cholerythrin and aminotransierase in serum were significantly higher than in CsA treated group and FasL treated group. The results of semi quantitative RT PCR showed higher expression levels of FasL and IL 12 in control group and mdrl treated group on the POD7. However, there was lower level or no detectable expression of FasL and IL 12 in CsA treated group and FasL treated group. Conclusion The therapy of DC transfected with FasL gene could induce immune tolerance of liver transplantation. The mechanism may have something to do with inducing apoptosis of activated lymphocytes and restrain the expression of IL 12.