Protective effect of microRNA-218 silencing on kidney tissue in STZ-induced diabetic rats / 中国病理生理杂志

ABSTRACT

AIM: To investigate the protective effect of microRNA-218 (miR-218) silencing on kidney tissue of streptozotocin (STZ)-induced diabetic nephropathy rats and the potential mechanism.METHODS: The diabetic rat model was established by a single intraperitoneal injection of STZ (50 mg/kg).Meanwhile, the miR-218 short hairpin RNA (shRNA) lentiviral vector was constructed.The Sprague-Dawley rats were randomly divided into 4 groups healthy control group, diabetes group, empty vector group and miR-218-shRNA group.The blood glucose, 24 h urinary protein, serum creatinine (SCr) and blood urea nitrogen (BUN) in the rats at different time points (4, 8 and 12 weeks) were measured by an automated analyzer.The expression of miR-218 was detected by RT-qPCR, while the expression of heme oxygenase-1 (HO-1), nephrin and p38 mitogen-activated protein kinase (p38 MAPK) at mRNA and protein levels in the kidney tissues was determined by RT-qPCR and Western blot.The caspase-3 activity was detected by caspase-3 activity assay kit, and the cell apoptosis of the kidney tissues was analyzed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL).RESULTS: Compared with healthy control group, the expression of miR-218 was significantly increased in STZ-treated rats.Meanwhile, the concentrations of blood glucose, 24 h urinary protein, SCr and BUN were significantly increased in STZ-treated rats (P<0.05).The mRNA and protein expression of HO-1 and nephrin was significantly decreased, while the level of phosphorylated p38 MAPK was significantly increased in STZ-treated rats.In addition, the activity of caspase-3 was also significantly increased in STZ-treated rats.When the model rats were infected with miR-218-shRNA, the expression of miR-218 was significantly decreased and the above effects were markedly reversed.Furthermore, TUNEL results showed that compared with diabetic group and empty vector group, miR-218 silencing significantly attenuated the cell apoptosis in the kidney tissues in miR-218-shRNA group.CONCLUSION: miR-218 is involved in the kidney injury in diabetic rats, and silencing of miR-218 by lentiviral vector-mediated miR-218-shRNA transfection effectively inhibits kidney cell apoptosis, suggesting that miR-218 is a potential target for the treatment of diabetic nephropathy.