Preliminary study of the effect of EPO pretreatment of bone marrow mesenchymal stem cells on preventing acute rejection after renal transplantation in rats / 器官移植

ABSTRACT

Objective To investigate the role of bone marrow mesenchymal stem cells (BMSCs) pretreated with erythropoietin (EPO) in the prevention of acute rejection after renal transplantation in rats. Methods BMSCs were divided into five groups: control group (without EPO), group A (pretreated with EPO at a final concentration of 10 IU/mL), group B (pretreated with EPO at a final concentration of 100 IU/mL), group C (pretreated with EPO at a final concentration of 500 IU/mL) and group D (pretreated with EPO at a final concentration of 1 000 IU/mL). In each group, the BMSCs were cultured for 24 h and 48 h. The proliferation rate of the BMSCs was determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. The BMSCs were divided into two groups: BMSC group (without EPO) and EPO-BMSC group (pretreated with EPO at a final concentration of 500 IU/mL). After 48 h culture, Western blot was adopted to measure the expression level of CXC chemokine receptor (CXCR) 4 protein in BMSCs. Wistar rats were used as the donors, and SD rats were utilized as the recipients to establish the rat models with acute rejection after renal transplantation. The recipient rats were randomly divided into four groups (n=6 in each group) including the control group (without any intervention), EPO group (injection of 1 mL of solution containing 500 IU EPO via tail vein immediately after surgery), BMSC group (injection of 1 mL of solution containing 1×106/mL BMSCs via tail vein immediately after surgery) and EPO-BMSC group (injection of 1 mL of solution containing 1×106/mL BMSCs cultured in vitro with 500 IU/mL EPO via tail vein). The level of serum creatinine (Scr) level was determined by Scr detection kit. Western blot was used to detect the expression levels of interferon (IFN)-γ and interleukin (IL)-4 proteins. Results After 24 h culture, the proliferation rate of BMSCs did not significantly differ among all groups (all P>0.05). After 48 h culture, the proliferation rate of BMSCs in group C (pretreated with EPO at a final concentration of 500 IU/mL) was significantly higher than that in the control group (P<0.05). Compared with the BMSC group, the expression level of CXCR4 protein on the surface of BMSCs was higher in the EPO-BMSC group (P<0.05). At 1 d after renal transplantation, the levels of Scr did not significantly differ among all groups (all P>0.05). At 5 d after operation, the levels of Scr in the EPO, BMSC and EPO-BMSC groups were significantly lower than that in the control group (all P<0.05). The level of Scr in the EPO-BMSC group was markedly lower than those in the EPO and BMSC groups (both P<0.05). At postoperative 1 d and 5 d, the expression levels of IL-4 protein in the kidney tissues did not significantly differ among all groups (all P>0.05). At 1 d after surgery, compared with control group, the expression levels of IFN-γ protein and IFN-γ/IL-4 ratio in the renal tissues in the EPO, BMSC and EPO-BMSC groups were significantly decreased to varying extents (all P<0.05), and similar results were obtained at 5 d after surgery (all P<0.05). The expression levels of IFN-γ protein and IFN-γ/IL-4 ratio in the EPO-BMSC group were significantly lower than those in the EPO group and BMSC group (both P<0.05). Conclusions BMSCs pretreated with EPO can prevent the incidence of acute rejection after renal transplantation and protect the renal graft function.