Elastic Fibers Distribution Difference At Rat Ventricular Myocardium Of Normal And Hypertension Rat

BackgroundComplete expression of heart function not only depends on the normal myocardial cells, but also depends on the normal structure and function of extracelluar matrix. Elastic fibers are the main ingredients of the myocardial interstitial connective tissue. Myocardial elastic fibers can enhance the elasticity of cardiac muscle, and the changes of its conformation and proportion directly affect myocardial function. There are plenty of researchs on the collagen of the heart at present, but the elastic fibers of cardiac is relatively poorly reported. As a common disease, Hypertension damages the structure of extracelluar matrix and cause ventricular remodeling, but the distribution of elastic fibers is still unknown in hypertension.ObjectiveThis study was specifically designed for the distributive characteristics of elastic fibers in normal and hypertensive rats, in order to lay the morphological basis for further exploring the cardiac physiological and establish the experimental basis for therapy of hypertention.Methods1. Establish hypertensive model with Sprague-Dawley(SD) rats:In accordance with the method of Rossi MA, NG-Nitro-L-arginine Methyl Ester (L-NAME 6 mg/kg·d) were gavaged to rats after waking for 3 weeks.2. 20 SD rats(3m) which are divided into normal adult rats and hypertensive adult rats, with 10 rats in each group, and then take the myocardial tissues. The observation of elastin site by immunohistochemistry, with the image analysis of elastic fibers quantitated, the dates processed with SPSS statistical software.3. The differences of elastic fibers between 2 groups were detected by Western blotting. Results1. Immunohistochemistry staining results:Elastic fibers were observed with the light microscope, and the staining was brown. Elastic fibers are widely distributed around the cells of the heart surrounding myocardial cells criss-crossly. Elastic fibers were relatively abundant in the epicardium, the periphery of cardiocyte and the small arterialwall. The morphology of the elastic fiber appeared hairs-like. Image analysis showed that:The Elastic fibers of the endocardium and the small arterialwall were increasing in hypertensive adult rats.2. Western blotting results:Elastic protein in each group was positive expression. Elastic protein of hypertensive rats were less than nomal rats. ConclusionElastic fibers were widely distributed in different parts of interstitial cells in SD rat heart. Elastic protein decreased in the endocardium and the small arterialwall in hypertentive rats.