协调性异种心脏移植排斥反应病理变化的动态研究

Dynamic pathological changes in concordant cardiac xenograft rejection

目的建立小鼠→大鼠异种心脏移植延迟性异种移植排斥反应(delayed xenograft rejection,DXR)动物模型,动态观察移植心脏组织病理和免疫病理变化,探讨DXR发生机制。方法袖套法建立小鼠→大鼠颈部异位异种心脏移植模型,设立未移植小鼠心脏为对照组(n=4),余组分别在移植术后3、8、16、24 h(每时相点n=4)供心仍跳动时取心,另一组(n=16)在供心停跳时取心并以此决定移植心脏存活时间。各组标本作HE染色和SABC法检测补体C3、IgM、IgG、E-selectin和巨噬细胞标记物CD68表达,结果行半定量评价。结果移植心脏HE染色表现为血管内皮损伤、血栓形成、心肌实质损伤、间质出血、炎症细胞浸润等排斥反应随移植术后时间逐渐加重趋势,完全排斥时部分心肌凝固性坏死及溶解、广泛间质出血、血管结构崩解及血管内血栓形成、严重炎症细胞浸润。移植术后供心平均存活时间(49.3±16.2)h。移植心脏免疫组化检测示:移植后任何时段均无C3沉积;从移植后3 h开始即有显著IgM沉积,且IgG沉积也逐渐增加;移植后3 h即有E-selectin表达,且表达逐渐增强,排斥时达高峰;从移植后3 h开始在浸润的炎症细胞中有逐渐增加的CD68阳性细胞。结论小鼠→大鼠异种心脏移植可作为DXR研究动物模型。内皮细胞激活、IgM和IgG抗体、巨噬细胞浸润参与DXR发生,但其发生不依赖于补体参与。

Objective To explore the mechanism of delayed xenograft rejection （DXR） by dynamic observation of histological and immunohistologic changes in mouse-to-rat cardiac xenografts. Methods A model of mouse-to-rat cardiac heterotopic xenotransplantation in neck was established by cuff technique. NIH mouse hearts not transplanted served as controls （n = 4）. Some xenograft recipients were killed and cardiac xenografts harvested at end of 3, 8, 16, 24 h （n =4 for each time point） after transplantation. The cardiac hearts （n = 16） of some xenograft recipients were not harvested until rejection time to determine their survival time. All heart samples were examined by HE and immunohistochemistry for semi-quantitative determination of antibodies including C3, IgM, IgG, E-selectin and macrophage marker- CD68. Results During the period after transplantation, the degree of rejection of xenografts became more and more serious till ultimate rejection. The mean survival time of the xenografts was （49.3± 16.2 ） h. Immunohistochemical examination showed C3 were not detected in the xenografts at any time during the course of rejection ; From 3 h after transplantation, obvious deposition of IgM was found in the grafts and IgG deposition got abundant; E-selectin expression was found as early as 3 h after transplantation and increased gradually; There was progressive infiltration by macrophages in the grafts. Conclusion Mouse-to-rat cardiac xenotransplantation can serve as an animal model of DXR. Endothelial cells activation, IgM and IgG, macrophage infiltration involve in DXR development except C3.