Effect of tehnisartan on the expression of integrin α3β1 in the glomeruli of diabetic rats

Objective To observe the effect of telmisartan on the expression of integrin α3β1 in the glomeruli of diabetic rats. Methods Twenty-four SD rats were divided into three groups; normal rat, diabetic rat, diabetic rats daily treated with telmisartan (3 mg·kg-1·d-1, a dosage that has no effects on blood pressure) for 6 weeks. Blood glucose, blood insulin, blood pressure, 24-hour proteinuria, serum creatinine and Ccr were measured. The expression of integrin α3β1 in glomeruli was determined by immunohistochemistry and Westernblot. The expression of TGF-β1mRNA was examined by RT-PCR. In addition, the renal tissue pathology was observed by light microscopy. Ultrastructure of the glomeruli was observed by electron microscope. Results (1) No significant differences of blood glucose, blood insulin and blood pressure were found between diabetic rats and telmisartan treated group. Compared to diabetic group, the levels of serum creatinine, blood urea nitrogen, 24-hour proteinuria in telmisartan treated group decreased significantly. Renal pathologic changes and ultrastructure changes of the glomeruli in telmisartan treated group were also improved.(2) The expression of integrin α3β1 mainly distributed along glomerular vessels. Compared to normal group, the expression of integrin α3β1 was decreased in glomeruli of diabetic rats. After 6-week treatment, telmisartan significantly up-regulated the expression of integrin α3β1 compared to the diabetic rats, whereas it significantly down-regulated the expression of TGF-β1mRNA (0.39±0.06 vs 0.48±0.04,P 0.05). Conclusion Telmisartan attenuates proteinuria, improves renal pathology and protects against renal function in early stage of diabetic nephropathy in rats, possibly through upregulating the expression of integrin α3β1 and down-regulating the expression of TGF-β11.