| BackgroundEssential hypertension is one of the high incidence diseases of cardiovascular system.Decompensated period can cause damage to target organs such as heart,brain and kidney.At present,the number of adults with hypertension is increasing in the world.The number of adults with hypertension in European and American countries has accounted for 30%of the total population,and males are higher than females.In China,the prevalence of hypertension is also increasing year by year.As of 2010,the number of adults with hypertension in China has accounted for one third of the total population,and increased by 9%annually.The number of deaths due to complications of hypertension is about 450,000 annually.Cardiac injury is a common complication of hypertension and the main cause of high mortality in patients with hypertension.Cardiac injury in patients with hypertension often begins with pathological hypertrophy of cardiac myocytes.Long--term pressure stimulation often causes hypertrophy of cardiac myocytes,which is related to the imbalance of autophagic regulation system in cardiac myocytes.The clinical effect of acupuncture on hypertension is satisfactory.It can not only reduce blood pressure,alleviate adverse reactions caused by oral antihypertensive western medicine,but also delay the progress of hypertension and regulate the level of autophagy of myocardial cells.ObjectiveThe purpose of this study is to explore the partial mechanism of electro-acupuncture in the treatment of spontaneous hypertensive myocardial hypertrophy from the perspective of autophagy of myocardial cells.By observing the changes of myocardial morphology,ultrastructure of myocardial cells and expression of autophagy-related proteins,the mechanism of electro-acupuncture "Baihui"and"Taichong"in the treatment of spontaneous hypertensive myocardial hypertrophy is preliminarily clarified,which provides certain theoretical guidance for for the treatment of hypertension by acupuncture.MethodsTwelve 12-week-old male Wistar-Kyoto(WKY)rats were selected as normal group and 24SHR rats of the same age were randomly divided into model group and electroacupuncture group(EA),12rats in each group.In EA group,after needling"Baihui"and"Taichong"on both sides,the electro-acupuncture apparatus was connected.The current intensity was 1mA,the frequency was 2Hz-15Hz,and the needle was retained for 20 minutes,once a day,for 30 consecutive days.The left ventricular hypertrophy and function were measured by echocardiography.The morphological changes of left ven tricular myocardium were observed by Masson staining.The ultrastructure of myocardial cells was observed by transmission electron microscopy.The expression of autophagy-related proteins Beclin-1 and LC3 in myocardium was detected by Western blot technique.Results(1)Comparison of systolic blood pressure of rats in each group:Compared with normal group,systolic blood pressure of rats in model group increased significantly(P<0.01),and decreased significa ntly in EA group(P<0.01).(2)Comparison of left ventricular echocardiographic results of rats in each group:Compared with the normal group,the left ventricular mass index(LVMI),left ventricular anterior wall diastolic(LVAWd),left ventricular posterior wall diastolic(LVPWd)and left ventricular intradiastolic diameter(LVWd)in the model group increased significantly(P<0.01),and the left ventricular internal diameter(LVWd)in the end diastolic phase increased significantly(P<0.01).Nal diameter diastolic(LVIDd)decreased significantly(P<0.01).Compared with model group,LVMI,LVAWd and LVPWd in EA group decreased significantly(P<0.01),while LVIDd increased significantly(P<0.01).(3)Changes of left ventricular myocardial morphology and intracellular structure in ratsof each group:Light microscopic observation after Masson staining:Compared with the model group,the width of myocardial cells in EA group increased to a certain extent,the arrangement of myocardial cells was relatively regular,the cell spacing was smaller,and the blue collagen fibers between cells were less.TEM observation:Compared with the model group,the degree of mitochondrial aggregation,cell edema and deformation,mitochondrial breakage in EA group was significantly reduced,and no autophagy and autophagic lysosome were found.(4)The expression of Beclin-1 and LC3-II in left ventricular myocardium of rats in each group:Compared with the normal group,the relative expression of Beclin-1 and LC3-II in myocardial tissue and LC3-II/LC3-I ratio in the model group increased significantly(P<0.01).Compared with model group,the relative expression of Beclin-1 and LC3-II in myocardial tissue and LC3-II/LC3-I ratio in EA group were significantly lower(P<0.01 or P<0.05).ConclusionElectro-acupuncture "Baihui" and "Taichong" can improve myocardial hypertrophy in SHR rats.The mechanism may be related to electro-acupuncture regulating the expression of Beclin-1 and LC3 and inhibiting the excessive autophagy of myocardial cells. |
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