高盐负荷上调SHR胸主动脉、肠系膜上动脉壁AT1和AT2受体表达实验研究

The Expression of AT1 and AT2 in aorta and superior mesenteric artery of Spontaneously Hypertensive Rats with Salt Load

目的:以自发性高血压大鼠(SHR)为研究对象,探讨动脉血管壁胶原成分、血管紧张素Ⅱ受体(ATR)AT1和AT2亚型蛋白表达的增龄性改变及高盐负荷对它们的影响。方法:雄性SHR60只,随机分为低盐组(0.4%NaCl,n=30)和高盐饮食组(4%NaCl,n=30)干预3周,测量血压后;胸主动脉及肠系膜上动脉石蜡切片Mallory染色法观察壁纤维化程度,免疫组化SABC法测定ATR蛋白表达。结果:高盐负荷后SHR大鼠的血压呈现明显升高(P<0.05);胸主动脉和肠系膜上动脉壁Ⅰ型和Ⅲ型胶原纤维沉积亦随增龄增多,高盐负荷会加重这一趋势(P<0.05);高盐负荷均能显著增加动脉壁AT1和AT2表达(P<0.01),而以肠系膜上动脉壁改变较为显著,但是对AT1/AT2比值无影响(P>0.05)。结论:高盐负荷可导致SHR大鼠血管壁重塑,血管壁局部ATR的改变可能是SHR大鼠血管壁重塑的机制之一,减少盐的摄入对预防高血压动脉病变的发生和发展有着重要的意义。

Objective： To investigate whether high salt intake lead to blood vessel remodeling in aortic ar tery and superior mesenteric artery walls of spontaneously hypertensive rats （SHR）, and whether the involvement of angiotensin receptor-1 （AT1） and angiotensin receptor-2 （AT2） in the development of remodeling. Methods： Male SHR, total 60, were randomly divided into normal-salt group （9 g/L NaC1） or high-sah one （40 g/L NaC1） , fed for 3 weeks. Before and after 3-week intervention of diet, the systolic blood pressures of SHR were measured and ana- lyzed by a tail-cuff method. After salt load, the proteins of AT1 and AT2 in arteries were detected by immunohisto- chemistry SABC staining in paraffin sections. Similarly, higher with high-salt diet in aortic artery （P〈 0.05）,the degree of the sediment of collagen fibers was detected using Mallory three-color staining. Results：l. High salt diet induced a significant increase of SBP and sediment of collagen fibers in SHR （P〈 O. 05）;2. AT1, AT2 expressed significantly, the same as AT1 （P 〈 0.01）, AT2 （P〈 O. 05） in superior mesenteric artery; 3. The ratio to AT1/ AT2 hadn ＇t this trend （P 〉 0.05）. Conclusion： Increasing expression of AT1, AT2 protein and ratio of them in lo cal large and medium sized arteries wall may be one of mechanisms of artery remodeling induced by salt load.