补体过度活化对急性移植物抗宿主病病理过程的影响

Influence of Excessive Complement Activation on Pathological Process of Acute Graft Versus Host Disease in Mice

本研究通过建立小鼠急性移植物抗宿主病(aGVHD)模型,研究aGVHD发病过程中补体系统的活化对病理过程的影响。选用近交系C57BL/6(H-2Kb)小鼠和BALB/c(H-2Kd)小鼠作为实验动物。模型组以前者作为供鼠,后者作为受鼠,给予受鼠8Gy60Coγ线全身照射后4-6小时进行骨髓细胞+脾细胞移植;对照组为同基因移植组。通过观察小鼠的体表特征、生存期以及体重变化跟踪模型组动物aGVHD的发生发展。采用流式细胞术鉴定移植后模型小鼠的基因型;运用酶联免疫吸附试验(ELISA)从蛋白水平检测整个发病过程中器官组织C3a、C5a等补体相关成分的分泌表达,同时运用荧光定量PCR技术从基因水平检测补体相关基因的表达变化;通过苏木精伊红(HE)染色对aGVHD所导致的组织损伤进行病理学分析,同时利用免疫荧光(IF)等实验技术检测补体相关成分在发病小鼠相应器官组织中的沉积,初步探讨其与组织病理损伤的内在联系。结果表明:模型组小鼠表现出典型的aGVHD特征:食欲下降、体重减轻、皱毛、弓背、活动减少、脱毛等;与对照组相比,模型组小鼠靶器官(肝脏)组织中补体相关成分的表达无论从蛋白水平还是基因水平上均有明显升高(p<0.05);组织病理学分析结果显示,模型组小鼠的靶器官组织中(肝脏的中央静脉和门管区)有显著的炎性细胞浸润,并且在浸润部位有明显的补体成分C3的沉积。结论:在小鼠aGVHD发病过程中,肝组织中的补体系统持续性地过度活化,产生的补体相关成分沉积于受损的肝组织内,沉积部位有明显的炎性细胞浸润,这说明补体系统的过度活化可能与aGVHD所导致的病理损伤有密切联系。

This study was aimed to explore the influence of excessive complement activation on the pathological process of acute graft-versus-host disease（aGVHD） in mice. A murine model with aGVHD was established by injecting cell mixture containing splenocytes and bone marrow cells at 2∶1 ratio from donor C57BL/6（H-2Kb） mice into recipient BALB/c（H-2Kd） mice within 4-6 hours after 8 Gy 60Co γ-ray total body irradiation. The mice received syngeneic bone marrow transplantation were used as control group. After transplantation, the mice were monitored daily for body weight and mortality. At day 14, all mice were sacrificed and each liver was freshly dissociated for histological analysis. The hepatic mRNA abundance for complement components C3a and C5a as well as receptors for these two anaphylatoxin were tested by real-time quantitative PCR method. And the levels of C3a and C5a production in liver were detected by ELISA. The deposition of complement C3 in liver was determined by immunofluoresence staining using frozen section. The results indicated that as compared with syngeneic bone-marrow transplantation control group, experimental animals underwent aGVHD characterized by weight loss, depilation, diarrhea and lassitude. Interestingly, the hepatic mRNA expression for complement anaphylatoxin family member C3a and C5a as well as their receptors C3aR and C5aR1 in mice with aGVHD were significantly up-regulated in comparison with control group （p0.05）. Consistently, the content of C3a and C5a in liver increased markedly in mice with aGVHD （p0.01）. For animals ongoing aGVHD, comple-ment component C3 depositions were observed in hepatic portal areas, around which massive inflammatory cell infiltration was also observed. It is concluded that in aGVHD animals, excessive complement activation occurs, and the activated complement components participate in pathological process of the aGVHD.