ABSTRACT
Objective To investigate the role of angiotensin Ⅱ receptors in metabolism of m yocardial collagen. Methods The collagen volume fraction(CVF), perivascular circumferential area(PVCA), hydroproline concentration(HC), ratio o f collagen type Ⅰto type Ⅲ(Ⅰ/Ⅲ),angiotensin Ⅱ(AngⅡ) content and the maximal binding capaci ty (Bmax) of ATRs were studied. The methods of radioimmunoassay(RIA),biochemistry assay, and pathological examin ation were used. Results Ventricular myocardial CVF, PVCA, HC, Ⅰ/Ⅲ, AngⅡ and B max of ATRs in WKY rats were significantly higher than those in sham -operation(SO)(P<0.05 or P<0.01),suggesting the collagen was abnormal ly accumulated in rats heart muscles. AngⅡ was positivily correlated with HC(r1=0.9045, P<0.01). After treament of Irbesartan, All above parameter were reduced significantly(P<0.05 or P<0.01), abnormally accumulated collagen was disap peared. While after treament of CGP42112A,an ATR2 antagonist, Bmax of ATRs was markedly decreased(P<0 .01), but CVF, PVCA, HC,Ⅰ/Ⅲ, AngⅡ showed little changes(P >0.05). Conclusion Obvious hyperplasia of myocardial collagens and remode ling of collagen network occurred after pressure overload. Local produced AngⅡ involves in the process,it's effects is mainly mediated by angiotensin Ⅱ 1 type receptor(ATR1)
ABSTRACT
AIM and METHODS: To investigate the role of angiotensin Ⅱ recepters(ATRs) in overload pressure-induced left ventricular hypertrophy. The rat abdominal aortic constraction model was adopted. At 10th week after operating, angiotensin Ⅱ in myocardium was measured by radioimmunoassay,tissue ATRs and its subtype were analysed by radioligand binding assay. RESULTS: The AngⅡ content in the operated group was significantly higher than that of the control group, LVMI was positively correlated with AngⅡ(r=0.8066,P