脾切除对心脏移植大鼠外周血淋巴细胞凋亡及调节性T淋巴细胞的影响

目的 探讨脾切除对同种异体心脏移植大鼠外周血淋巴细胞凋亡及调节性T淋巴细胞的影响.方法 以Wistar大鼠为供者、SD大鼠为受者,进行腹部异位心脏移植,同时切除受者的脾脏(心脏移植切脾组),并以不切脾者为对照(心脏移植对照组),另设不行任何处理的对照组和单纯切脾的单纯切脾组.术后第1、3、5、7天.取各组受者的移植心脏和外周血,观察移植心脏的组织学变化和细胞超微结构改变情况,以流式细胞仪检测外周血淋巴细胞的凋亡率及CD4+ CD25+ T淋巴细胞的变化,逆转录聚合酶链反应检测CD4+ CD25+ T淋巴细胞上Foxp3 mRNA的表达情况,记录移植心脏的存活时间.结果 心脏移植对照组移植心脏存活时间为(7.47±2.24)d,心脏移植切脾组移植心脏存活时间为(17.63±4.54)d,二者间的差异有统计学意义(P<0.05).心脏移植对照组的移植心脏肿胀,质硬,色暗,间质水肿、出血,弥漫性炎症细胞浸润,大量心肌细胞坏死、溶解,横纹不清;心脏移植切脾组的移植心脏质软,色红,局部灰白,外膜下以及细胞间局灶性水肿,炎症细胞浸润,心肌细胞结构完整,横纹清晰;心脏移植切脾组的细胞超微结构改变轻于心脏移植对照组.心脏移植切脾组术后第5天和第7天的淋巴细胞凋亡率分别为(7.62±2.15)%和(9.41±3.82)%,明显高于心脏移植对照组(P<0.05,P<0.05).心脏移植切脾组术后第3、5、7天时的CD4+ CD25+ T淋巴细胞明显多于心脏移植对照组(P<0.01,P<0.01,P<0.01),其Foxp3 mRNA的表达也较心脏移植对照组明显上调.结论 脾切除使心脏移植大鼠外周血淋巴细胞凋亡率增加,调节性T淋巴细胞增多,其Foxp3 mRNA表达上调,这些变化与移植心脏病理改变呈负相关.

The effect of splenectomy on peripheral lymphocyte apoptosis and CD4+ CD25+ Treg cells in rat with heart transplantation

Objective To investigate the effect of splenectomy on peripheral lymphocyte apoptosis and CD4+ CD25+ Treg cells in rat with heart transplantation. Methods Abdominal heterotopic heart transplantation was performed from Wistar (donors) to SD (recipients) rats. Splenectomy was done at the same time in recipients (heart graft splenectomy group), non-splenectomy recipients (heart graft group), single splenectomy in SD rats (spleneetomy group), and SD rats (no operation) were designed as the control group. The transplanted hearts and peripheral blood in each group were collected on the 1st, 3rd, 5th and 7th day after operation. Histopathological and ultrastructural changes in transplanted hearts were observed by microscope and electronic microscope. Apoptosis rate of peripheral lymphocytes and CD4+ CD25+ Treg cells were measured by flow cytometry. The expression of Foxp3 mRNA in CD4+ CD25+ Treg cells was detected by RT-PCR, and survival time of the transplanted hearts was recorded. Results The survival time of the transplanted hearts in heart graft splenectomy group was 17.63±4.54 days, significantly longer than that in heart graft group (7.47±2.24 days) (P<0.05). The transplanted hearts in heart graft group were swelling, hard, dark, with interstitial edema, hemorrhage, diffuse infiltration of inflammatory cells, necrosis and cytolysis of a lot of myocardial cells, blurred cross striations; The transplanted hearts in heart graft splenectomy group were soft, red, partially gray white, with focal edema of subepicardial cells,infiltration of inflammatory cells, intact myocardial cell structure, and clear cross striations; Compared to heart graft group, the ultrastructural changes of transplanted hearts in heart graft splenectomy group were lighter significantly. On the 5th and 7th day after operation, apoptosis of peripheral lymphocytes in heart graft splenectomy group was (7.62±2.15)% and (9.41±3.82)% respectively, significantly higher than in heart graft group (both P<0.05). On the 3rd, 5 th and 7th day after operation, the number of CD4+ CD25+ Treg cells in heart graft splenectomy group was more (all P<0.01), and the expression level of Foxp3 mRNA higher than in heart graft group. Conclusion Splenectomy can increase apoptosis rate of peripheral blood lymphocytes and the number of regulatory T lymphocytes, and up-regulate the Foxp3 mRNA regulation in rats with heart transplantation, which has a negative correlation with pathological changes of transplanted hearts.