自发性高血压大鼠心血管重塑及其机制探讨

目的 :探讨自发性高血压大鼠 (SHR)左心室与肠系膜动脉重塑的发生与机制。方法 :选用 13周龄的SHR 10只、Wistar Kyoto大鼠 (WKY大鼠 ) 10只分为两组 :SHR组、WKY组。实验期 13周。观察指标 :血压、LVW BW、左室厚度 体重、中膜厚度 管腔半径、中膜面积 管腔面积、管腔半径 血管半径、心肌及肠系膜动脉的形态学 (光镜、电镜 )、血浆、心肌、肠系膜动脉血管紧张素Ⅱ (AngⅡ )浓度及血浆、心肌心钠素 (ANF)浓度。结果 :SHR组大鼠左室重量 体重 (LVW BW)、左室厚度 体重、中膜厚度 管腔半径、中膜面积 管腔面积、血浆及心肌ANF均比WKY组大鼠高 ,SHR组管腔半径 血管半径、心肌及肠系膜动脉AngⅡ浓度比WKY组低 (P均 <0 .0 5 ) ;心肌HE染色WKY组心肌纤维排列整齐、致密 ,心肌纤维无断裂 ,SHR组心肌纤维排列稀疏 ,中间可见断裂 ;心肌及肠系膜动脉电镜观察SHR组超微结构有明显损伤性改变 ,胶原纤维明显增生。结论 :2 6周龄SHR左心室与肠系膜动脉有明显的重塑现象 ;SHR血浆、心肌、肠系膜动脉的AngⅡ无明显增高 ,AngⅡ水平升高不是SHR高血压及其心血管重塑的原因 ;肠系膜动脉重塑的主要原因可能系血管壁的细胞外基质 (ECM)堆积 ,而不是平滑肌细胞增殖。

Discussion of Remodeling and Its Mechanism of Left Ventricle and Resistance Vessel in Spontaneously Hypertension Rats

Objective: To research remodeling and its mechanism of left ventricle and resistance vessel in spontaneously hypertension rats. Methods: Ten 13 weeks old spontaneously hypertension rats as SHR group, and ten homogenous Wistar Kyoto rats as normal control group(WKY group) were selected. Blood pressure of rats was periodically monitored. After 13 weeks, all rats was put to death, excising heart, the left ventricle weight(LVW) and thickness were measured, and then LVW/BW and left ventricle thickness/BW was computed. Specimen of left ventricle and the second grade branch of mesenteric arteries were observed by light and transmission electron microscope and media thickness to lumen radius ratio, media to lumen area ratio, lumen to vessel radius ratio were calculated by a computer Image Analysis System. AngⅡ level of plasma,left ventricle myocardium, mesenteric arteries and ANF level of plasma and left ventricle myocardium were measured by radioimmunoassay. Results: Blood pressure and LVW/BW,left ventricle thickness/BW, mesenteric arteries media thickness to lumen radius ratio, media to lumen area ratio, ANF level of plasma and left ventricle myocardium of SHR group were higher than those of WKY group. Lumen to vessel radius ratio in SHR group was lower. AngⅡ level of plasma, left ventricle myocardium, mesenteric arteries in SHR group was same or lower than that in WKY group. Left ventricle and mesenteric arteries modulation in structure especially fibrosis were obvious in SHR group. Conclusion: Remolding of left ventricle and resistance vessel in 26 weeks SHR is obvious; AngⅡ level of plasma, left ventricle myocardium, mesenteric arteries in SHR is not higher than that in WKY, hypertention and remodeling of cardiovascular in SHR is not due to increasing AngⅡ level. The main reason of remodeling in resistance vessels is probably that extracellular matrix (ECM) of vessel wall increases and not that VSMCs of vessel media hyperplasia.