The Effects And Mechanisms Of (Pro) Renin Receptor On Cardiac Damage In Hypertensive Rats With Aortic Constriction

ObjectiveWe use abdominal aortic coarctation hypertension rats as experimental model,to observe the role of rat myocardial tissue phospholipase C beta 3(phosphalipase C beta 3,the PLC beta 3)in prorenin receptor(pro)renin receptor(P)RR)induced myocardial injury and myocardial fibrosis,to detect the expression,activity and function mechanism of plc-beta3 and its downstream signal transduction factor,to provide a theoretical basis for in-depth understanding of the hypertension pathogenesis.MethodA total of 50 hypertension rat models were prepared from selected male SD rats of the same weight and stable blood pressure using conventional abdominal aorta restriction surgery method.Rats were randomly divided into five groups,10 rats in each group.The results were as follows: 1.Sham operation group(Control,C): The surgical treatment is identical to other groups except that no abdominal aortic ligation was applied.Postoperative routine feeding was applied after the surgery operation;II.Hypertension group(Aortic ligation,AL): abdominal aortic constriction,routine postoperative feeding;III group.U73122(U): abdominal aortic constriction,postoperative PLC-beta 3 inhibitor U73122(40 g/kg/d)treatment;IV.Group HRP(H): constriction of abdominal aorta,postoperative(P)RR inhibitor HRP(4 g/kg/d)treatment;V.U73122 group and HRP group(U+H): abdominal aortic constriction,postoperative U73122 and HRP combined treatment;the treatment time duration was 4 weeks.Rat tail artery blood pressure was measured periodically in the whole duration of experiment.After the completion of the above experiment,the following tests were carried out: RT-PCR detection of ACE2,collagen I,AOG,renin,MAS,collagen III mRNA expression in myocardial tissues;protein expression of ACE2,collagen I,AOG,renin,MAS,collagen III in the myocardial tissue were measured by Western Blot;radioimmunoassay(RIA)for angI and AngII concentrations in myocardial tissue.Result1.Measurement of blood pressure in ratsThe control group(100+3mmHg),arterial hypertension rats have significantly increased blood pressure(P<0.05).Treated with u73122,HRP or the combination of u73122 and HRP,the blood pressure of groups u73122 group(128+5mmHg),(HRP)group(131+6mmHg)and U73122+HRP group(126+6mmHg)were significantly lower(P<0.05)than that of hypertension group(155+5mmHg)compared,but was still higher than that in sham operation group.2.Detection of myocardial AOG,Renin,ACE2,MAS,Collagen I,Collagen III mRNA2.1The mRNA expression level of AOGCompared with sham operation group,heart tissue AOG mRNA level in hypertensive group rats increased significantly,the difference was statistically significant(P<0.01).Compared with hypertension group,using U73122,HRP,treatment alone or in combination,lowered AOG mRNA levels significantly(P<0.01).2.2 The mRNA expression ofACE2The level of ACE2 mRNA in the heart of hypertensive rats was significantly decreased than that of sham operated rats(P<0.01).Compared with hypertensive group,after treatment,the ACE2 mRNA level in the heart of the three groups were all higher significantly(P<0.01)after treatment.2.3The mRNA expression of MASIn the hypertensive group,MAS mRNA level was decreased in the heart(P<0.05).After using U73122 HRP the treatment,the cardiac MAS expression in other three groups of rats were increased(P<0.05).2.4 The level of Collagen?mRNA expressionCompared with sham operated group,the level of Collagen?mRNA in hypertensive group was increased in the heart(P<0.01).After treatment,the collagen?mRNA level in the heart in the other three groups were all decreased significantly(P<0.01).2.5 The mRNA expression ofCollagen?In hypertensive group,Collagen? mRNA was increased in the heart(P<0.01).After using U73122,HRP,treatment alone or in combination,lowered Collagen?mRNA levels significantly(P<0.01).2.6 The expression level of mRNA ReninCompared with the sham operation group as blank control,myocardial tissue Renin mRNA level in hypertensive group rats increased significantly(P<0.05).Compared with hypertension group,drug intervention group U73122,group HRP and group U73122+HRP have significantly decreased Renin mRNA level(P<0.01).3.The protein levels of cardiac AOG,Renin,ACE2,MAS,Collagen? and Collagen?:3.1 The protein level of AOGin the heartCompared with controls AOG protein in hypertensive group was higher in the heart(P<0.01).After the treatment,the cardiac AOG expression was decreased in other three groups of rats(P<0.01).3.2 The protein level of ACE2 in the heartCompared with sham operated group,ACE2 protein level in hypertensive group was decreased in the heart(P<0.01).After treatment in other three groups,the ACE2 protein levels in the heart were all higher significantly(P<0.05).3.3 The protein level of cardiacMASIn the hypertensive group,MAS protein level was decreased in the heart(P<0.05).After using U73122 HRP the treatment,the cardiac MAS expression in other three groups of rats were increased(P<0.05).3.4 The protein level ofCollagen? in the heartCompared with sham operation group,Collagen?protein level in hypertensive group was higher in the heart(P<0.01).After the treatment in other three groups,the cardiac Collagen? level was decreased(P<0.01).3.5 The protein level of cardiacCollagen?The expression of Collagen? protein in the heart of hypertensive rats was lower than that in controls(P<0.05).Compared with hypertensive group,the Collagen? protein levels in the heart in both HRP and U73122+HRP groups were increased(P<0.05),but no significant change after U73122 treatment.3.6 The protein level of cardiac ReninCompared with the sham operation group as blank control,Renin protein level in the hypertensive group was increased in the heart(P<0.05).After the treatment,the cardiac Renin protein level in the HRP and U73122+HRP groups were decreased(P<0.05).3.7 The protein level of Ang?in the heartCompared with controls Ang? protein in hypertensive group was higher in the heart(P<0.05).After the treatment,the cardiacAng?expression was decreased in other three groups of rats(P<0.01).Conclusion1.The expression of AOG in the heart of hypertensive rats was increased,After treatment with HRP and U73122 AOG levels decreased,indicating that AOG was involved in the process of myocardial injury.2.Cardiac collagen I,collagen III expression in hypertensive rats increased.After application of HRP and u73122 and combined treatment.The expression levels of both decreased,at the different extent,showed that collagen I,collagen III and other downstream factors are involved in cardiac tissue damage.3.In hyptertensive rats,cardiac ACE2,MAS decreased.After HRP and U73122 treatment,cardiac ACE2,MAS expression levels increased and blood pressure dropped,showing that block of the signal transduction pathway can reverse the cardiovascular damage to cardioprotective role.4.During eenal hypertension in rat,the expression of cardiac Aog,renin and Ang II increased.After treatment of U73122,and HRP cardiac Aog,renin and Ang II levels decreased,indicating the combination therapy can reduce the expression of the damaged components of RAS.5.Ang II caused hypertrophy of cultured myocardial cells,which increased PRR expression in the cells.After treatment of HRP and U73122,the expression of PRR in myocytes decreased significantly.6.Administration of(P)RR and PLC-b3 inhibitors reduced the activity of the damaged components of RAS,which is a significance in reduction of risks in hypertension and cardiovascular events.