Effect Of Insulin On The Expression Of Myosin Light Chain Kinase In The Kidney Of Diabetic Rats

Objective To study the effect of insulin on the expression of myosin light chain kinase(MLCK) in the kindey of diabetic rats by constructing the experimental model of diabetic rats. To investigate the correlation between MLCK and mechanism of diabetic nephropathy (DN) by observing the dynamic chang of MLCK.Methods Eighty male Sprague-Dawley( SD )rats were (?) to adapt environment for a week. The rats were randomly divided into control and experimental groups.To construct the experimental animal model by receiving an intraperitoneal injection streptozotocin (STZ) When the blood sugar of the rats was higher than 16.7mmol/L and kept at least 5 days, the animal model of diabetic rat should have been established. The diabetic rats were randomly divided into diabetic group(4 weeks and 12 weeks) and insulin- treated group(4 weeks and 12 weeks).The treated-group rats were administered subcutaneous injects of protamine zine insulin 3u/d. At 4 weeks and 12 weeks later, rats were anesthetized with injection of sodium pentbarbital. After collecting of blood samples from common carotid artery for determinations of glucose level, the one kidney was perfused with ice-cold PBS. Thereafter, the kidney was exised, and immersed in 4% polyoxymethylene .The fixed kidneys were embedded in paraffin and sectioned for immuohistochemical and HE stainting. The other kidney was freezed to preserve at -80℃ for expression of MLCK semi-quantified by western-blot. Results The experimental animal model of diabetic rat was constructed successfully. The glomerulus had obviously pathologic changes by observing HE staihing of kindey sections and analyzing some biochemistic index. The expression of MLCK was stronger positive cells in glomerulus, renal tubule, and glomerular arteriolar and artery by observing immuohisochemical results. And the expression of MLCK had a significative change in glomerulus. The level of the MLCK was lower in renal of 4-week diabetic rats (4 weeks 33 ± 8%) than one in normal rats, whereas the changes were not obvious in renal of...