【Objective】 To investigate the effects of cyclosporine A (CsA) on the molecular expression of the lymphocytes and the relationship with the pathological changes after the allogenic heart transplantation. 【Methods】 To use SD rats as the donors and Wistar rats as recipients. The animals were divided into two groups: allogenic heart transplantation Wistar rats with cyclosporine A intervention were used as experimental group and without the cyclosporine A intervention as control group. Before the operation

24 h

72 h

7 d

10 d

and 12d after the transplantation

the lymphocyte infiltrating in myocardial tissues was observed using fluorescence antibodies. CD4

CD8

and P59 mRNA expression level were analyzed by quantified PCR. The histopathological changes in myocardial tissues were monitored to judge the allogenic rejection. 【Results】 (1) 24 h after heart transplantation the transcription and expression of peripheral blood lymphocytes genes were reduced..(2)CD4+

CD8+ lymphcoyte infiltration increased after the transplantation and theⅡdegree rejection pathological changes happened between d3 and d7 after heart transplantation.(3) Cyclosporine A did not affect CD4+ and CD8+ expression and the lymphocytes infiltration in the first 3 days after the transplantation. But CsA significantly reduced the CD4+ infiltration degree in myocardial tissues between d3 and d7. (4) In both groups

CsA was not able to completely block P59 gene expression. (5) Although cyclosporine A did not effectively suppress lymphocyte CD4 gene positive expression but it could suppress CD8 gene transcription. 【Conclusions】 The immunosuppressive effects of CsA was majorly happened in d3~d7 after the allogenic heart transplantation. The peripheral blood lymphocytes genes expression

lymphocytes infiltration in myocardial tissues were correlated with the pathological changes. This finding may provide a better understanding of the clinical use of the CsA for the allogenic heart transplantation patients.