The effect of splenectomy on peripheral lymphocyte apoptosis and CD4+ CD25+ Treg cells in rat with heart transplantation / 中华器官移植杂志

ABSTRACT

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.