胰岛素抵抗高血压大鼠心肌纤维化的研究

目的　探讨胰岛素抵抗时心肌纤维化形成的可能机制。方法　以高蔗糖喂养形成的胰岛素抵抗高血压大鼠(IRHR)和正常对照 SD大鼠为研究对象 ,观察其心肌纤维化指标 (心肌组织羟脯氨酸含量及胶原容积分数 ) ,并进行相关性分析及形态学观察。结果　 IRHR组血压、血清胰岛素、左心室相对重量、心肌组织羟脯氨酸含量及胶原容积分数均明显高于对照组 ,其胰岛素敏感指数明显降低。形态学观察发现其心肌间质胶原纤维明显增多。相关分析发现左心室相对重量、心肌组织羟脯氨酸含量及胶原容积分数均与血清胰岛素呈明显正相关 ,与胰岛素敏感指数呈负相关。结论　高蔗糖饲料喂养 SD大鼠可以形成胰岛素抵抗和高血压 ,其心肌纤维化的形成与胰岛素抵抗、代偿性高胰岛素血症有关 ,胰岛素抵抗可能是高血压心肌纤维化发生的机制之一

A study of the myocardial fibrosis in insulin resistant hypertensive rats

Objective To study the possible mechanisms by which myocardial fibrosis is formed in insulin resistance. Methods The insulin resistant hypertensive rats (IRHR)model was reproduced by feeding Sprague-Dawley(SD)rats for 8 weeks on a high-sucrose chow. SD rats (n=10) were studied as a control group. Left ventricular relative mass(LVRM), L-Hydroxyproline(H-Pro) content and collagen volume fraction(CVF) in myocardiac tissue were determined and morphological changes were investigated. Some correlation analyses were made. Results (1)Blood pressure and serum insulin in IRHR were higher than those in control group, insulin sensitive index(ISI) was lower in IRHR. LVSW/BW,H-Pro content and CVF in myocardiac tissue in IRHR were higher than those in control group.(2) LVSW/BW,H-Pro content and CVF in myocardiac tissue were significantly correlated with serum insulin positively and with ISI inversely. (3)Increased interstitial collagenous fibers were found in IRHR by optical microscopy and electronmicrograph. Conclusions High-sucrose feeding can induce insulin resistance and hypertension in the SD rats which are not genetically destined to become hypertensive. The formation of myocardial fibrosis in IRHR may be correlated with insulin resistance and compensatory hyperinsulinemia. Insulin resistance may be one of the mechanisms by which myocardial fibrosis is formed in insulin resistant hypertensive rats.