Increase in Matrix Metalloproteinase–9 Activities in Spontaneously Hypertensive Hyperlipidemic Rats

Abstract

Abstract: : Purpose: Matrix metalloproteinases (MMPs) play an important role in the atherosclerosis by degenerating extracellular matrix. Progression of atherosclerosis due to the sustained hypertension and hyperlipidemia often concomitant with retinopathy. MMPs are unquestionably vital to retinopathy, but their physiologic mechanism remains to be elucidated. Therefore, we aimed at examining changes of MMPs in a new model of spontaneously hypertensive hyperlipidemic rats (SHHR) (Clin. Exp. Pharmacol. Physiol. 2003 30(8): 537–44). SHHR were obtained by crossbreeding spontaneously hypertensive rats with spontaneously hyperlipidemic rats. In SHHR, systolic blood pressure is more than 150 mmHg, and plasma cholesterol is more than 150 mg/dl. The purpose of this study is to investigate the activities of MMP–2 and 9 in vitreous and plasma of SHHR as an atherosclerotic model. Methods: Male SHHR and Wistar–Kyoto rats as the control were fed on a normal diet for eight months. The activities of MMP–2 and 9 in vitreous and plasma were determined by geratin zymography and the MMP–9 expression in retina was determined by immunochemistry. Results: The activities of MMP–9 significantly increased in vitreous and plasma in SHHR compared with those in control rats. The activities of MMP–2 increased in plasma in SHHR, but little change was observed in vitreous. Conclusions: It is suggested that MMP–9 may become the indication and the target for a therapeutic approach to retinopathy.

Keywords: vitreous • retina