Animal Experiment Study On Treating Renovascular Hypertension By Swietenia Macrophylla Fructus Extract

BackgroundHigh blood pressure is a harmful factor of cardiovascular disease,which can cause many serious consequences,such as cerebral infarction,myocardial infarction,renal failure,etc.At present,the commonly used antihypertensive drugs caused high fluctuation of blood pressure[1],and more adverse reactions;therefore,it is necessary to search for new safe and effective antihypertensive drugs.In Southeast Asia,local people relieve their blood pressure by chewing and swallowing Swietenia nacrophylla fructus or taking its decoction[2].But there are few modern studies on the effect of Swietenia macrophylla fructus on its antihypertensive activity.PurposeBased on Renovascular hypertensive(RH)rat model,blood pressure,biochemistry and pathological changes of viscera were checked after Swietenia Macrophylla fructus extract administration,to explore the antihypertensive activity of Swietenia Macrophylla fructus and its mechanisms.Methods1.Establishment of animal mode:Renovascular hypertensive(RH)rat model was established by using two kidney one clip(2K1C)method,the left renal artery was cramped by silver clip.12 weeks after modeling,the rat systolic blood pressure was measured>150 mmHg for 3 consecutive days,indicating successful model making.2.The preparation of Swietenia macrophylla fructus extracts(SME):Ultrasonic extraction of Swietenia macrophylla fructus was done with petroleum ether,ethyl acetate and methanol in a sequential manner.The methanol extracts was used in this study.3.Grouping and administration:The rats were randomly divided into model group,positive group,SME high dose group and SME low dose group,and sham group.The rats were administrated for 8 weeks and blood pressure was observed during this process.4.Detection of biochemistry index:Blood level of renin(PRA),angiotensin ?(Ang?),and aldosterone(ALD)were determined by ELISA.The concentration of serum creatinine(CREA)and urea nitrogen(BUN)was determined by Catalyst One automatic biochemical analyzer.5.Pathological observation:The right kidney,thoracic aorta and heart were stained by HE.And the pathological changes were observed.6.Statistical analysis:One-way analysis of variance(ANOVA)was done by using SPSS 22.0 software.Results1 Blood pressure measurement:The systolic pressure of SME high dose group and SME low dose group were lower than that of model group,and the differences had statistical significance(P<0.01).The diastolic pressure of SME high dose group and SME low dose group were lower than that of model group,and the differences had statistical significance(P<0.01).2 Detection of serum RAAS:The values of PRA,Ang ? and ALD of model group were higher than that of sham group respectively,and the differences had statistical significance(P<0.01).The values of PRA,Ang? and ALD of SME high dose group and SME low dose group were lower than that of model group respectively,and the differences had statistical significance(P<0.01).3 Detection of serum CREA and BUN:The CREA and BUN concentration of model group were all higher than that of sham group,and the differences had statistical significance(P<0.01).Compared with the model group,the SME low dose group and the SME high dose group both had lower values of CREA and BUN,and the differences had not statistical significance(P>0.05).4.Pathology observation:The heart and right kidney coefficient of sham group,positive group,SME high dose group and SME low dose group were all lower than that of model group,and the differences had statistical significance.Glomerular atrophy,renal tubulointerstitial connective tissue hyperplasia and fibroblasts could be seen in rat kidney of model group,the degree of renal injury in the other groups was less than that of the model group.Compared with the model group,the remodeling of thoracic aorta in positive group,SME high dose group and SME low dose group was improved in varying degrees.ConclusionIn summary,SME can effectively reduce blood pressure in RH rats.SME can also significantly inhibit RAAS activity and visceral remodeling.SME can reduce Ang ?and ALD levels through RAAS inhibition,then inhibiting vascular contraction and water-sodium reabsorption,at last reduce blood pressure.