Protective effects of Eucommia lignans against hypertensive renal injury by inhibiting expression of aldose reductase

To investigate the protective effects and the underlying mechanism of Eucommia lignans against hypertensive renal injury. Ten-week-old Wistar Kyoto rats and age matched spontaneously hypertension rats were used in the study. The SHR were randomly divided into 4 groups (n = 7 for each group) and received different treatment for 16 weeks, which including saline, Captopril, Epalrestat and Eucommia lignans, respectively. System blood pressures of the rats were monitored once every 4 weeks. N-Acetyl-β-d-glucosaminidase (NAG) activity and the ratio of albumin and urinary creatinine were chosen as the indices of kidney function. Then the structure and renal collagen type III expression of glomerular basement membrane were observed by microscopy and the renal aldose reductase (AR) expression was measured by immunohistochemistry. In vitro, the proliferation of mesangial cells induced by AngII was assayed by MTT, and the mRNA expression of AR was measured by RT-real-time PCR. The renal function, evaluated by NAG enzyme activity and the ratio of albumin to urinary creatinine, was significantly ameliorated by Eucommia lignans treatment. Meanwhile, Eucommia lignans decreased both the protein (P < 0.05) and the mRNA expressed lever of AR (P < 0.05). Eucommia lignans also decreased the high expression of collagen type III in SHR (P < 0.05) and inhibited the proliferation of renal mesangial cells induced by AngII (P < 0.05). Eucommia lignans have protective effects against hypertensive renal injury, and the protective effects may be partly due to inhibition of aldose reductase.