| Chronic hypertension increases the stress load on the heart.In order to adapt to the increased load,compensatory hypertrophy occurs in myocardial cells,leading to hypertrophy.Cardiac hypertrophy can significantly increase the incidence of sudden cardiac death and heart failure and has been listed as an independent risk factor affecting the incidence and death of cardiovascular disease.Therefore,the treatment of hypertension should not only be limited to the control of blood pressure,but also focus on the reversal of left ventricular hypertrophy and prevention of myocardial fibrosis,so as to restore the normal structure of the myocardium and protect the cardiac function.The PI3K/Akt pathway is involved in cell growth,proliferation,apoptosis,metabolism and other regulatory responses,and studies have shown that the PI3K/Akt pathway is closely related to the occurrence and development of myocardial hypertrophy.Many studies indicate that acupuncture has shown significant effects in reversing cardiac hypertrophy and preventing cardiac fibrosis,and has fewer side effects than western medicine.However,there are few studies on the regulating effect of acupuncture on the PI3K/AKT signaling pathway,and no studies have demonstrated whether the treatment of myocardial hypertrophy by acupuncture is related to the regulation of the PI3K/AKT signaling pathway.ObjectiveOur study aims to find out whether the antihypertrophic effects of acupuncture are related to the PI3K/Akt signaling pathway.Therefore,in this study,SHR rats were used as spontaneous hypertension models,and electroacupuncture on LR3 and DU20 was used as an intervention method.Western blot,Real-Time PCR,Elisa and small animal ultrasound imaging technology were applied to explore the effects of acupuncture on myocardial hypertrophy.MethodsTwelve male wistar-kyoto(WKY)rats at 12 weeks old were selected as the normal group.Twenty-four spontaneous hypertension rats(SHR)of the same age were randomly divided into model group and electroacupuncture group.In the electroacupuncture group,the rats were punctured with filiform needles at DU20 and bilateral LR3 acupoints for 1-2 mm,respectively.Needles on "DU20" and the right "LR3" are respectively connected to the positive and negative poles of the electroacupuncture instrument,and the needle is retained for 20 min.Acupuncture was performed once a day in the morning for 30 consecutive days.The blank group and model group were placed in the same fixation device as the electroacupuncture group for 20 min every day.Blood pressure was measured 1 day before acupuncture and 6,12,18,24 and 30 days after acupuncture.At the end of the 30-day intervention,the left ventricular hypertrophy and function[including LVPWT,IVST,LVEDD and LVEF]were measured by high-resolution echocardiography.Based on weighing rats left ventricular wet weight,and calculate the left ventricular mass index(LVMI)of rats.Histopathological changes of myocardium were observed by HE staining.By enzyme-linked immunosorbent assay(Elisa)to detect each rat myocardial tissue in angiotensin Ⅱ(Ang Ⅱ)and atrial natriuretic peptide(ANP)protein expression level,and through the real-time fluorescent quantitative PCR(Real-Time PCR)and Western blot method(Western blot)technology to detect myocardial tissue of rats in phosphatidyl inositol kinase(PI3K),protein kinase B(Akt),mammalian target of rapamycin(mTOR),homologous protein phosphatase-tension protein(PTEN)protein and RNA expression.According to the statistical results,the antihypertensive effect of electroacupuncture "DU20" and "LR3" on SHR and the reversal effect of myocardial hypertrophy were evaluated.The mechanism of electroacupuncture in reducing hypertrophy of hypertensive myocardium was analyzedResults1.Comparison of blood pressure measurement results of rats in each group:compared with the normal group,systolic blood pressure of rats in the model group increased significantly at each time point(P<0.01).After 30 days of intervention,the systolic blood pressure of the electroacupuncture group was significantly lower than that of the model group(P<0.01).This indicated that electroacupuncture,"DU20" and "LR3" could effectively reduce SHR blood pressure.2.Comparison of left ventricular mass index and echocardiographic results in each group:compared with the normal group,LVMI,LVPWT and IVST in the model group were significantly increased(P<0.01),while LVEDD and LVEF were significantly decreased(P<0.01).Compared with the model group,in the electroacupuncture group,LVMI,LVPWT and IVST were significantly decreased(P<0.01),while LVEDD and LVEF were significantly increased(P<0.05,P<0.01).This indicated that electroacupuncture,"DU20"and "LR3" could effectively reduce myocardial hypertrophy and improve cardiac ej ection function in SHR rats.3.Comparison of myocardial tissue morphology of rats in each group:the size of myocardial cells of rats in the normal group was moderate,and the cells were orderly and compact.Compared with the normal group,the arrangement of myocardial cells in the model group was relatively disordered,with significantly larger cell cross sectional area,wider cell spacing,and larger hyperchromatic nuclei.Compared with the model group,the number of nuclei increased,the cross sectional area of cardiac myocytes was relatively small,and the cell spacing was relatively narrow.The results showed that electroacupuncture "DU20" and"LR3" could effectively reduce the degree of hypertrophy of myocardial cells and the damage of stress load on the morphology of myocardial tissue.4.Each group rats Elisa test results contrast:compared with normal group,model group,the myocardial tissue ANP and Ang Ⅱ protein expression level decreased significantly,(P<0.01).Compared with model group,the curative group of myocardial tissue ANP and Ang Ⅱprotein expression level decreased significantly.Electroacupuncture at "DU20" and "LR3"can effectively reduce the Ang Ⅱ secretion in myocardial cells,and reduce the content of myocardial hypertrophy standard indicators of ANP.5.Comparison of real-time PCR and western-blot results of rats in each group:compared with the normal group,the expressions of PI3K,Akt,mTOR protein and RNA were significantly decreased in the model group(P<0.01),and the expressions of PTEN protein and RNA were significantly increased(P<0.01).Compared with the model group,the expressions of PI3K,Akt,mTOR protein and RNA were significantly increased in the electroacupuncture group(P<0.01),and the expressions of PTEN protein and RNA were significantly decreased(P<0.05).ConclusionLong-term high blood pressure in SHRs resulted in increased left ventricular wall thickness,increased myocardial cell volume and decreased ejection function.This indicated that SHR showed myocardial remodeling characterized by myocardial hypertrophy,accompanied by cardiac functional injury.Electroacupuncture at "DU20" and "LR3" can effectively reduce SHR systolic blood pressure levels,reduce the myocardial hypertrophy on the structure and function of the myocardial damage,reduce the myocardial cells of ANP and Ang Ⅱ expression level,including its mechanism may be through PI3K/Akt pathway activation of myocardial cells,regulating their growth proliferation level implementation. |
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