肢体移植排斥反应中细胞凋亡及致死基因表达

Study on expression of apoptosis and lethal gene during acute rejection in limb allograft

目的探讨同种异体肢体移植急性排斥反应时细胞凋亡及致死基因Fas、Fas配体(FasL)表达的作用及其意义。方法建立近交系SD大鼠与Wistar大鼠间原位异体肢体移植模型。实验观察组为异基因组,SD大鼠为供体,Wistar大鼠为受体;对照组为同基因移植组,在Wistar大鼠之间移植。分别进行左腿原位移植术。术后第1,3,5,7d分别取移植肢体组织进行病理学检查及电镜扫描,采用原位末端标记法(TUNEL)检测移植肢体中的凋亡细胞,免疫组化方法检测移植肢体中Fas、FasL表达的变化。结果实验组大鼠在术后发生由轻到重的急性排斥反应,对照组无明显排斥现象。实验组的移植物细胞凋亡数均明显高于对照组,凋亡细胞主要分布在血管内皮细胞及皮肤基底层细胞;术后第7d因严重排斥使小血管广泛栓塞。异基因肢体移植组的移植物中Fas/FasL表达增高,并与病理学检查及细胞凋亡程度一致。结论Fas、FasL介导的血管内皮细胞凋亡在大鼠异基因肢体移植急性排斥反应中发挥重要作用,可作为判断移植肢体预后及监测排斥反应的重要指标。

Objective To explore the changes of apoptosis and expression of Fas and Fas-ligand(FasL) during acute rejection of limb allograft.Methods Orthotopic limb allograft was performed on inbred SD rat and inbred Wistar rat.Experimental group:allogenic transplant group (SD→Wistar),control group:(Wistar→Wistar).The grafts were harvested on day 1,3,5,7 after operation.All grafts samples were subjected to histologyical examination and electron microscopic examination.Apoptosis cells of grafts were monitored by terminal UTP nick-end labeling (TUNEL) method,and the Fas/FasL level detected by using immunohistochemistry method.Results Histologically,mild,moderate and then severe acute rejection occurred gradually after operation in the experimental group.But none of control group had the histological evidence of acute rejection.The TUNEL showed that the number of apoptosis cells in the experimental group were significantly higher than that in the control.Apoptosis cells were mainly distributed in vascular endothelial cells and basilar membrane cell of skin.Generally embolism in small vessels occurred due to severe rejection on the day 7 after operation.Fas/FasL expression in allografts were increased in correapondant with the degree of the apoptotic and histologyical damage.Conclusion The Fas/FasL mediated apoptosis of vascular endothelial cells play an important role in acute rejection of limb allograft in rats,and might be an important parameter to evaluate the rejection and prognosis in the limb allograft.