不同年龄自发性高血压大鼠血浆和心室肌AngⅡ及心室肌ATR表达

Expression of Plasma,AngⅡ and ATR in Ventricular Myocardium of Spontaneously Hypertensive Rats with Different Age

目的:探讨年龄对血浆和心室肌血管紧张素Ⅱ(AngⅡ)水平及心室肌受体血管紧张素受体(ATR)表达的影响。方法:雄性自发性高血压大鼠(SHR)60只均分为幼年组(7周龄)、成年组(26周龄)及老年组(51周龄);取各组大鼠SHR血浆及心室肌组织,采用ELISA法检测循环血液和心室肌组织匀浆中的AngⅡ水平,取左心室石蜡染色、切片观察间质纤维化程度,免疫组化SABC法测定ATR亚型AT1和AT2表达。结果:3组SHR大鼠循环血浆中AngⅡ含量随年龄增大而增加、但差异无统计学意义(P>0.05),心室肌匀浆中AngⅡ含量随年龄增加而升高、差异有统计学意义(P<0.01);3组SHR大鼠心肌IOD值随年龄增加而增加,差异有统计学意义(P<0.01),且心肌胶原纤维沉积随年龄增加而明显增加,尤其在老年组;3组SHR大鼠左室心肌中AT1的GD值随年龄增加而降低,AT2的GD值在幼年组均高于成年及老年组(P<0.05);老年组和成年组的AT1/AT2值均低于幼年组(P<0.01)。结论:年龄对SHR循环血液中AngII影响较小,但可引起心肌组织局部血管紧张素受体(ATR)的改变,导致心肌间质纤维化。

Objective: To investigate changes of age on expressions of plsma,AngII and ATR in spontaneously hypertensive rats (SHR). Methods: 60 male SHR were randomly divided into young group (7 w),adult group (26 w) and elder group (51 w).Collecting SHR plasma and ventricular muscle tissue and adopting ELISA assay to detect the expression of angiotensin Ⅱ(Ang II) level from circulating blood and ventricular muscle tissue homogenate;interstitial fibrosis was observed by Mallory staining with paraffin section,and ATR protein expression was measured by immunohistochemical SABC method. Results: AngII content increased with age in three groups SHR circulating plasma,differences were not statistically significant ( P >0.05).AngII content in ventricular muscle homogenate increased with age,differences were statistically significant ( P <0.01).Ventricular muscle IOD value increased with age in three groups,differences were statistically significant ( P <0.01);ventricular muscle collagen fiber sediment increased with age,especially in elder group;GD value of AT1 in left ventricular increased with age in all three groups SHR,GD value of AT2 in young group was higher that that of elder group ( P >0.05);AT1/AT2 value of both adult group and elder group were lower than that of young group ( P <0.01). Conclusion: Age has little effect on circulating AngⅡ in SHR,but it can cause local ATR changes in myocardial tissue and myocardial interstitial fibrosis.