Renal expression of Cyclooxygenase-2 in diabetic nephropathy and the effects of Losartan

Objective To observe the renal expression of cyclooxygenase-2(COX-2) in diabetic nephropathy rats and the effects of Losartan as angiotensin II type 1(AT1) receptor antagonist.Methods Twenty-eight diabetic Sprague-Dawley(SD) rats induced with intraperitoneal injection of streptozotocin were randomly divided into two groups: diabetic rats without therapy(group D,n=14) and diabetic rats treated with Losartan(group L,n=14).Twenty SD rats were used as the control(group N).The urine and blood samples in 24h were collected after the treatment with Losartan for 10 weeks.The rats were killed and the renal expression of COX-2 was determined with immunohistochemistry.Results Expression of COX-2 in the nephridial tissue and the concentration of urinary thromboxane B_2(TXB_2) in group D were significantly higher than those in group N(P0.01).The expression of COX-2 and urinary TXB_2 decreased significantly after the treatment with Losartan(P0.01).Conclusion The expression of COX-2 and urinary TXB_2 increase significantly in the diabetic rats.After treatment with Losartan,the expression of COX-2 and urinary TXB_2 decrease significantly,which may be one of the protective mechanisms for kidney.