〔Abstract〕 Objective To investigate the expression of triple motif protein 21(TRIM21) at different time points in Cisplatin induced acute kidney injury(Cis-AKI) mouse model and its correlation with pathological score.Methods Acute kidney injury(AKI) model was induced by intraperitoneal injection of cisplatin(20 mg/kg).Peripheral blood serum was collected at 12,24,48 and 72 h,respectively.Body weight and kidney mass were also recorded.The dynamic changes of serum creatinine(SCr) and urea nitrogen(BUN) were detected.The expressions of TRIM21 protein and endoplasmic reticulum stress(ERS) proteins GRP78,GRP94,P-elf2α and CHOP were detected by Western blot.HE staining was used to observe the pathology of renal tissue and analyze the correlation between the expression of TRIM21 protein at different time points.Results Compared with the control group,the renal body ratio of Cis-AKI mice significantly increased at 48 h and 72 h(P