Abstract: Objective：To investigate the molecular mechanism of bone marrow mesenchymal stem cells (BM-MSCs) in repairing cisplatininduced acute renal injury. Methods：The rats were injected 6 mg/kg of cisplatin intraperitoneally, and bone marrow mesenchymal stem cells (BM-MSCs group) or PBS (PBS group) were injected respectively via tail vein after 24 hours. The rats without injecting cisplatin were selected as a normal control group. The repair effect of BM-MSCs on renal injury was observed by HE staining and immunohistochemistry. In addition, NRK-52E cells were cultured in vitro and treated with cisplatin for 6 hours. Then, NRK52E cells were continued to culture for 48 hours or co-cultured with BM-MSCs for 48 hours, and NRK-52E cells untreated with cisplatin were used as a control. The expression levels of miR-92b and its target gene PTEN were detected by qRT-PCR, and the expression level of p-Akt by western blot. Results：HE staining showed that the tubular protein casts in BM-MSCs group were significantly less than that in PBS group, and that the renal tubular structure was significantly improved in BM-MSCs group. Immunohistochemical staining indicated that the number of cells expressing proliferating cell nuclear antigen (PCNA) in BM-MSCs group (131.0±14.4) was significantly higher than that in PBS group (42.2±6.1, t=11.28, P<0.01). qRT-PCR results showed that in the vivo experiment, compared with the expression level of miR-92b and PTEN in the normal control group (1.11±0.78，1.01±0.21), PBS group were (4.64±1.06) and (0.61±0.2),respectively (all P<0.05); BM-MSCs group were (2.27±0.81) and (1.1±0.1),respectively(all P<0.05). In vitro experiment, compared with the expression level of miR-92b andPTEN in the negative control group (1.12±0.77，1.02±0.13), cisplatin group were (7.64±0.72) and (0.58±0.2),respectively (all P<0.05), cell group were (4.38±0.50) and (1.15±0.23),respectively(all P<0.05). Western blot results showed that compared with the expression level of p-Akt in cisplatin group (0.96±0.18), p-Akt expression in cell group was (2.11±0.11, P<0.01). Conclusion：BM-MSCs may repair the cisplatininduced acute renal injury via down-regulating the expression level of miR-92b.