To investigate the effect of domestic sirolimus (yixinke) and the original product Rapamycin on the cytology of transplanted host in vitro and in vivo.

T24 cells were cultured in vitro, and Yixinke and Rapamycin were treated respectively. The cell proliferation was rate assessed by CKK-8 kit. An in vivo model of heterotopic heart transplantation in mice was established, and the mice were divided into a control group (without surgery) , a transplantation group (Tx group without therapy) , Yixinke treatment group (Tx+YXK group) and Rapamycin treatment group (Tx+RAPA group) . Beating of the transplanted heart, the composition of the recipient's spleen cells, and infiltration of immune cells into the spleen and the grafts were monitored. The main immune cells detected by flow cytometry were dendritic cells, CD8⁺ T cells and regulatory T cells. Histopathological examination, immunohistochemical staining and gray level difference analysis were used to compare the infiltration of immune cells between the two treatment groups. The ANOVA and two-independent t-tests were used for statistical analysis.

In vitro experiments showed that the effect of domestic sirolimus on the proliferation of T24 cells was the same as that of the original product (P > 0.05) . In vivo experiments showed that the beating of the transplanted heart in the Tx group stopped on the 7th day, and in the Tx+YXK group and Tx+ RAPA group, the beating of the transplanted heart was still normal and strong on the 10th day. (1) Flow cytometric analysis of spleen revealed that compared with the control group and Tx group, the number of CD11c⁺I- A⁺CD86⁺DC cells and CD8⁺ lymphocytes (15.88±4.73, 22.90±3.86 vs 4.51±1.57, 5.40±2.54, 6.32±0.98, 6.75±1.34 vs 3.03±1.12, 3.23±0.97) in Tx+RAPA group and Tx+YXK group were all decreased (P < 0.05) , and the number of CD4⁺CD25⁺Foxp3⁺ positive cells in the Tx+ RAPA group increased (P < 0.05) . There was no significant difference in the number of CD11c⁺I-A⁺CD86⁺DC, CD8⁺ lymphocytes, CD4⁺CD25⁺Foxp3⁺ regulatory T cells between Tx+YXK group and Tx+Rapa group (P > 0.05) . (2) According to immunohistochemical staining and gray level difference analysis for the transplanted heart, there was no significant difference in the number of CD4, CD8, Ido and CD11b between Tx group, Tx+YXK group and Tx+Rapa group (P > 0.05) . Compared with Tx group, the number of CD11c and Foxp3 positive cells infiltrated in Tx+RAPA group and Tx+YXK group (25143.52±3525.12 vs 12936.30±766.94, 14240.60±3124.67, 500.78±238.33 vs 46.05±68.16, 49.22±25.82) was lower. There was no significant difference between Tx+YXK group and Tx+Rapa group (P > 0.05) . (3) Immunohistochemical staining and gray level difference analysis for the spleen of the model mice showed that the number of CD4 and CD8 positive cells infiltrated in the Tx group was less than that in the Tx+YXK group and Tx+RAPA group, but the difference was not statistically significant (P > 0.05) . Between the Tx+YXK group and Tx+Rapa group, the difference of IOD value of various cell staining was not statistically significant.

Our results showed that cell infiltration into the transplanted heart and spleen in the Yixinke and conventional drug treatment groups was similar. The effects of Yixinke and the conventional drug on cell proliferation in vitro, anti-rejection following transplantation and immune cells in vivo were all similar.