Mir-21 inhibits proliferation of renal tubular epithelial cells in diabetic nephropathy rats by regulating the expression of smad-associated proteins

To analyze the inhibition of miR-21 on proliferation of renal tubular epithelial cells in diabetic nephropathy (DN) rats by regulating the expression of Smad-associated proteins. the rat renal tubular epithelial cell lines were selected for cell recovery, culture, passage, and cryopreservation, and were then divided into high glucose group, high glucose virus group, high glucose no-load virus group and low glucose group for carrying out cell transfection. The cell proliferative capacity was detected by MTT assay, and Smad7 level was determined by Western blot. A total of 40 SD rats were selected and randomly divided into control group, model group, virus group and no-load virus group. All rats were anesthetized and their left kidneys were excised. Specifically, after operation, the control group was given standard feed, and other groups were given a diet with high fat, glucose and cholesterol. It was confirmed that all these groups were successfully modeled. Rats in virus group and no-load virus group were anesthetized, and were injected with miR-21 overexpression lentivirus and no-load virus through caudal vein. After that, these rats were killed after anesthesia, and tissue slices were made. The rat kidney tissue image was observed by HE staining, and Smad7, Smad2 and Smad3 levels were determined by Western blot. The inhibiting effect of miR-21 on the proliferation of renal tubular epithelial cells in DN rats by regulating the expression of Smad-associated proteins was then analyzed. compared with the control group, the levels of FBG, 24h urine protein and urea nitrogen were slightly higher in the virus group, no-load virus group and model group, and the difference was statistically significant (P<0.05). Specifically, in the virus group, model group and no-load virus group, FBG level was all >= 7.0mmol/L on average, 24h urine protein level was >140mg/L and urea nitrogen level was >8.2mmol/L, indicating that diabetes modeling in these three groups is successful. In the control group, mesangial cells and mesangial matrix did not proliferate, glomerulus size was normal, basilar membrane was not thickened, and no obvious renal tubular lesions were observed; in the model group, glomerulus was swollen, mesangial matrix and a small amount of mesangial cells proliferated, and renal tubule epithelium swelled; the changes in the no-load virus group were similar to that in the model group; in the virus group, mesangial cells did not significantly proliferate, but slight proliferation of mesangial matrix and vacuolar degeneration of renal tubular epithelial cells were observed. Compared with the control group, Smad7, Smad2 and Smad3 levels in the model group and no-load virus group were significantly higher, and the same was suitable for the virus group. The difference was statistically significant (P<0.05). The proliferative capacity of renal tubular epithelial cells in each group increased with the time. Among all groups, the proliferative capacity of renal tubular epithelial cells in high and low glucose virus groups was significantly lower than that in the high glucose group and high glucose no-load virus group, and the difference was statistically significant (P<0.05). Smad7 protein level in renal tubular epithelial cells of high glucose no-load virus group was significantly lower than that in low and high glucose groups and high glucose no-load virus group, and the difference was statistically significant (P<0.05). miR-21 can inhibit the proliferation of renal tubular epithelial cell in DN rats, which may be associated with the regulating effect of miR-21 on the expression of Smad-associated proteins.