同种异体大鼠的主动脉移植后影响移植物钙化的因素分析

目的：探讨同种异体大鼠的主动脉移植后影响移植物钙化的因素。方法：研究分为2组，即异基因组和同基因组。异基因组中SD大鼠为供体，Wistar大鼠为受体；同基因组中受体和供体均为Wistar大鼠。两组再随机分为5个小组，每组8只，进行大鼠同种异体带瓣主动脉腹主动脉的异位移植。分别于术后2、4、8、12、16wk，以流式细胞术测定大鼠血液中CD25、CD71的表达。取出移植物，用原子火焰吸收法测定钙的含量，用光镜和电镜观察移植物的形态学变化，用免疫组化染色法测动脉壁CD40的表达：结果：（1）异基因组移植后各个时间点，CD40、CD25和CD71的表达均较同基因组高（P〈0．01）。异基因组CD25、CD71和CD40表达的高峰主要在移植后的早期（2～4wk），此后表达的水平逐渐下降，12nk后维持在低水平。（2）异基因组移植物的钙含量从移植后第4周开始升高，随着时间的推移逐渐升高，在12wk达到高峰，此后进入平台期。同基因组各个时间点的钙含量无差别（P〉0．05）。（3）移植后异基因组的移植物出现内皮细胞脱落和平滑肌细胞坏死。结论：同种瓣移植后移植物中的钙含量与免疫排斥反应关系密切；钙含量并不与时间完全呈正相关，在移植后4wk才开始钙化：随着时间的推移，钙含量逐渐升高，在12wk达到高峰，此后进入平台期。移植后不同时间点移植物中的钙含量并不与当时的免疫排斥反应的程度成正相关，二者互相影响。

Analysis of the factors which influence allograft calcification after aorta transplantation of allogenetic rat

AIM: To explore the factors which influence the calcification of homograft after aorta transplantation of allogenetic rat. METHODS: The research was devided into 2 groups: allogene group and isogenenic group. Allogene group: SD -->Wistar. Isogenenic group: Wistar to Wistar. Aortic valve homograft was heterotopically allografted onto abdominal aorta. The rats were sacrificed in batches at 2, 4, 8, 12 and 16 weeks postoperatively. Blood samples were obtained for accessing the expression of CD25, CD71, and AVH was obtained for accessing the calcium level and the expression of CD40. At the same time, the change of endotheliocyte and smooth muscle cells were observed with transmission electron microscope. RESULTS: (1)Compared with the isogene group, the expression of CD40, CD25 and CD71 in allogene group was much higher at each time point and reached peak at 2-4 weeks after operation. (2)The calcium level in allogene group increased at 4 weeks after operation and reached the peak at 12 weeks after operation. No significant difference in calcium level was found in isogenenic group over 5 different periods. (3)Exfoliation of endotheliacytes as well as necrosis of smooth muscle cells were observed in the graft in allogene group. CONCLUSION: The calcium level of homograft had a relation with immunological rejection. The calcification began at 4 weeks postoperation; the calcium level of homogaft increased gradually and reached the peak at 12 weeks postoperation and then maintained on a stable level.