ABSTRACT
OBJECTIVE To explore the mechanism of Tingli dazao xiefei decoction on ventricular remodeling in model rats with heart failure after myocardial infarction. METHODS The rat model of heart failure after myocardial infarction was established by ligation of anterior descending branch of left coronary artery， which was divided into 8 groups： sham operation group， model group， A779 group （1 mg/kg）， A779 （1 mg/kg）+Tingli dazao xiefei decoction equivalent-dose group （0.8 g/kg）， A779 （1 mg/kg） +Tingli dazao xiefei decoction high-dose group （1.6 g/kg）， Tingli dazao xiefei decoction equivalent-dose group （0.8 g/kg）， Tingli dazao xiefei decoction high-dose group （1.6 g/kg） and losartan potassium group （10 mg/kg）. Each group was given equal volume of distilled water or corresponding drugs intragastrically for 4 weeks. Masson staining was used to determine the distribution of collagen fibers in rat myocardium. The content of hydroxyproline （Hyp） in myocardium was determined by alkaline hydrolyzation. The expressions of type Ⅰ and Ⅲ collagen （COLⅠ， COLⅢ）in myocardium were detected by immunohisto-chemistry. Myocardial fibrosis-related indexes such as matrix metalloproteinase-2 （MMP-2）， MMP-9， tissue inhibitor of metalloproteinase-1 （TIMP-1） and soluble suppression of tumorigenicity-2 （sST-2） were detected by ELISA. The protein expressions of angiotensin converting enzyme 2-angiotensin-（1-7）-Mas [ACE2-Ang-（1-7）-Mas] axis were detected by Western blot. RESULTS Compared with sham operation group， myocardial cells in model group and A779 group were disordered， collagen fiber deposition was significantly increased and myocardial fibrosis was obvious； the Hyp content and MMP-2， MMP-9， sST-2 levels were increased， and COL Ⅰ and COL Ⅲ positive expressions were significantly enhanced； TIMP-1 level， protein expressions of ACE2， Ang-（1-7） and Mas were significantly decreased （P＜0.05）. Compared with model group， above indexes of Tingli dazao xiefei decoction equivalent-dose and high-dose groups were improved to different extents. Compared with A779 group， A779+Tingli dazao xiefei decoction equivalent-dose and A779+high-dose groups could improve myocardial arrangement and collagen distribution， reduce the Hyp content and MMP-2， MMP-9 levels， reduce positive expressions of COL Ⅰ and COL Ⅲ （P＜0.05）， but couldn’t improve Ang-（1-7） and Mas protein expression. CONCLUSIONS Tingli dazao xiefei decoction can improve ventricular remodeling in myocardial failure model rats after myocardial infarction by improving the expression of ACE2- Ang（- 1-7）-Mas axis proteins.
ABSTRACT
OBJECTIVE：To in vestigate the effects of quercetin （Que）on the expressio n of angiotensin Ⅱ（AngⅡ）-induced myocardial contractile proteins of primary rats through angiotensin-converting enzyme 2-angiotensin-（1-7）-Mas （ACE2-Ang- （1-7）-Mas）axis. METHODS ：Cardiac tissue of rats aged 1-2 d were collected ，and primary cardiomyocytes were isolated and cultured. The gene silencing model of cardiomyocytes ACE2 was constructed. Experiments were divided into 12 groups. Among them，AngⅡ group，AngⅡ+ small interference RNA （siRNA）group，and Ang Ⅱ+ A 779 group were the model groups ；AngⅡ+ losartan group was positive control group ；AngⅡ+Que40 group，AngⅡ+Que80 group，AngⅡ+siRNA+Que40 group，AngⅡ+ siRNA+Que80 group，AngⅡ+A779+Que40 group and Ang Ⅱ+A779+Que80 group were the experimental groups ；blank group and siRNA group were set up. Ang Ⅱ concentration was 1×10－6 mol/L；siRNA final concentration was 50 nmol/L；Que concentration was 40 and 80 μmol/L；A779（Mas receptor inhibitor ）concentration was 1 μmol/L；losartan concentration was 1×10－4 mol/L. mRNA and protein expression of ACE 2，Ang-（1-7） and Mas in primary cardiomyocytes were detected ；the expressions of myocardial contractile proteins were also determined ，such as Na +/Ca2+ exchange channel （NCX），calcium pump （SERCA2a）， phosphoprotein （PLB）. RESULTS ：Compared with Ang Ⅱ group，mRNA expression of Mas was increased significantly in Ang Ⅱ + Que 80 group （P＜0.05）；mRNA expression of ACE2 and Mas were increased significantly in Ang Ⅱ + CZ0210-01） losartan group （P＜0.05）. Compared with Ang Ⅱ group，the 851136165@qq.com protein expression of ACE 2 and Ang- （1-7） were increased significantly in Ang Ⅱ+ Que 40 group（P＜0.05）；compared with Ang Ⅱ + siRNA group ，the protein expression of Ang-（1-7）were increased significantly in Ang Ⅱ+ siRNA+Que 40 group（P＜0.05）；compared with Ang Ⅱ+A779 group，the protein expression of Ang- （1-7）were increased significantly in Ang Ⅱ+A779+ Que 40 group（P＜0.05）. Compared with Ang Ⅱ group，the protein expression of NCX was decreased in Ang Ⅱ+Que40 group（P＜0.05），protein expression of NCX was reduced in Ang Ⅱ+ losartan group （P＜0.05）；compared with Ang Ⅱ+A779 group，the protein expression of NCX was decreased in Ang Ⅱ+A779+ Que80 group （P＜0.05）. CONCLUSIONS ：Que improves the expression of Ang Ⅱ -induced ACE 2-Ang-（1-7）-Mas axis in cardiomyocyte model to some extent ，so as to regulate myocardial contractile protein.
ABSTRACT
The renin angiotensin system(RAS)includes two counterbalance axes:the ACE/Ang Ⅱ/AT1 axis and the ACE2/Ang(1-7)/Mas axis.The RAS can regulate glucose and lipid metabolism in adipose tissue.Most of evi-dences demonstrated that the ACE/Ang Ⅱ/AT1 axis can induce glucose metabolism disorders in adipose tissue, while ACE2/Ang(1-7)/Mas axis improves glucose metabolism.The RAS,which is over activated in obese patient, has been considered to be a potential link among obesity,dyslipidemia and insulin resistance.The effect of ACE/AngⅡ/AT1 axis and ACE2/Ang(1-7)/Mas axis on lipid and glucose metabolism in adipose tissue should be futh-er investigated,and we may find a new target for improving glucose and lipid metabolism.
ABSTRACT
AIM:To investigate the effects of exercise training on the progression from prehypertension to hy -pertension,blood pressure regulation and the angiotensin-converting enzyme 2(ACE2)-angiotensin(Ang)(1-7)-MAS axis activation in cardiovascular centers ,and to elucidate the central mechanisms of exercise training postponing hyperten -sion progression.METHODS:The male spontaneously hypertensive rats(SHR;n=20,5 weeks old)and normotensive Wistar Kyoto(WKY)rats(n=20)were randomly assigned to sedentary(Sed)group and exercise training(ExT)group. The trained rats run on a treadmill in moderate-intensity for 20 weeks.Systolic blood pressure(SBP)was measured by tail-cuff method.The baroreflex sensitivity(BRS)was assessed by intravenous injection of phenylephrine.The expression of ACE2 and MAS receptor at mRNA and protein levels in baroreflex centers were determined by real-time PCR and Western blot,respectively.Alterations of BRS were evaluated before and after intracerebroventricular injection of MAS receptor ago -nist Ang(1-7)and its antagonist A779,respectively.RESULTS:Compared with SHR +Sed group,exercise training since prehypertension significantly postponed the development of hypertension ,delayed the hypertension progression ,and decreased SBP in both SHR and WKY rats(P<0.05).Exercise training enhanced blood pressure regulation and improved the BRS in SHR(P<0.01).The expression of ACE2 and MAS receptor at mRNA and protein levels in the baroreflex cen-ters(rostral ventrolateral medulla ,nucleus tract solitarius and paraventricular nucleus )were up-regulated in SHR +ExT group(P<0.05).Central administration of A779 abolished the benefits of exercise-induced improvement of BRS in SHR +ExT group(P<0.01).In contrast,Ang(1-7)improved the BRS in both SHR +Sed group and SHR +ExT group(P<0.05).CONCLUSION:Exercise training postpones hypertension progression and improves blood pressure regula -tion,which may be associated with the activation of central ACE 2-Ang(1-7)-Mas axis.