| Epidemiological studies have indicated that high dietary intakes of saturated fat,cholesterol,total fat and total calories positively correlate with mortality from cardiovascular disease in most developed countries.However,a low incidence of CVD has been suggested to co-exist with the intake of a high fat diet in France.This phenomenon known as the ‘French paradox' is thought to be related to the high prevalence of red wine consumption in France.Many studies have shown that resveratrol,which is abundant in red wine,exerts cardiovascular protective effects and plays an important role in the‘French paradox',but it does not fully explain the phenomenon.Some studies reported that tannic acid(TA)is present at varying floristic compositions,and it is found at relatively higher concentrations in red wines than white wines.Recent studies have implicated antioxidant activities,radical scavenger,inhibition of lipid oxidation,lowering of plasma triacylglycerol and cholesterol leveamong the diverse effects of TA.Medicinal plants with antioxidant properties were recently reported to also confer cardioprotective effects.Thus,we speculate that the effects of TA,in addition to those of resveratrol,may contribute to the ‘French paradox'.An improved understanding of the chain of events that lead to end-stage coronary artery disease have been known in cardiovascular research during the past decades.These achievements have been accompanied by therapeutic advances that now make it possible to treatment at virtually every stage in the progression of advanced cardiovascular disease,from asymptomatic patients exposed to the risk of developing coronary atherosclerosis to patients with end-stage cardiac failure.By stopping this chain of events,perhaps at some sites,preventing or slowing the development of symptomatic heart disease andhopefully prolonging life may be possible.Further information regarding the underlying pathophysiology can be obtained from many opportunities,the fundamental mechanisms of action of interruption designed to prevent and/or intervent the development of cardiac ischemia and heart failure and for effectting favorably the natural history of various forms of cardiovasular disease.It has achieved significant achievement to treat myocardial injury,heart failure by improving living habits,controling risk factors,optimizing diet,using of antiplatelet drugs,angiotensin converting enzyme(ACE)inhibitor,angiotensin receptor blockers(ARB)enzyme,beta blockers blockers,spironolactone and etiological.However,being huge population of china,The cost of our health has taken up too much.Prevention of cardiovascular disease can only be achieved inflection point.The cardioprotection effect of tannic acid will be gradually clarified by intensive study.It could also play an importent role for TA in preventing CVD(cardiovascular disease)and future food industry.TA,as one of the most abundant reserve materials of plants,is a polyphenolic compound which is widely present in fruits and vegetables and is commonly consumed in food and beverages.It has been widely used in the food industry as a preservative and is generally regarded as a safe food additive.The chemical structure of TA is C76H52O46,which is comprised of five galloyl esters and a glucose.Many studies have demonstrated the antimutagenic,anticarcinogenic and antibactericidal activities of TA.However,the exact mechanism by which TA acts to prevent a high fat diet from increasing the risk for CVD is not well-understood but may be related to its radical scavenging activities,inhibition of lipid oxidation,lowering of plasma triacylglycerol and cholesterol level,as well as other as yet undiscovered functions.Therefore,we speculate that TA may be able to exert a certain level of cardioprotection.In conclusion,except the resveratrol,cardioprotective effects of red wine has been gradually attention in recent years.However,the protective effects involves its mechanism of TA injection against organs injury induced by ISOremain unknown.Based upon the above mentioned TA injection,in my thesis,we use techniques such as molecular biology,pathomorphology,cytology,Immunohistochemistry and others to systematically study the following subjects:(1)Effect of tannic acid on ISO induced cardiac remodeling and its mechanisms in rats;(2)Effect of tannic acid on oxidative stress,inflammatory changes and dyslipidemias in ISO induced cardiac remodeling in rats;(3)Effects of TA on cardioprotective and potential mechanisms in ISO-induced acute myocardial injury.Part1 Effect of tannic acid on ISO induced cardiac remodeling and its mechanisms in ratsObjective: Cardiac remodeling is a hallmark of hypertension induced pathophysiology.The aims of the study were to investigate whether tannic acid(TA)prevent ISO-induced cardiac remodeling in rats and to explore its related mechanism(s).Methods: 50 male Sprague-Dawley(SD)rats were randomly divided into five groups of 10 animals per group,control,ISO,low-dose TA(L-TA),middle-dose TA(M-TA)and high-dose TA(H-TA)groups.ISO(5 mg·kg/d)was given subcutaneously continuously 7 days to induce cardiac remodeling in rats.The control group animals received i.p.injections with isovolumic saline.Therapeutic groups were given TA(20,40,and 60 mg/kg/d)by intragastric administration for two weeks after ISO treatment one week.The control group and ISO group were given isovolumic saline by intragastric administration.Results:1 Effect of TA on heart function of cardiac remodeling induced by ISO in rats Given i.p.injections of ISO continuously 7 days,compared with control group,the level of-dp/dtmax and LVEDP in ISO group was increased significantly,and there was significant difference between the two groups(P<0.05).the level of +dp/dtmax in ISO group was decreased significantly,there was significant difference between the two groups(P<0.05).HR and LVSP has no significant changes.The level of-dp/dtmax and LVEDP in TA group(20mg/kg/d,40 mg and 60mg/kg/d)was decreased significantly;and the level of +dp/dtmax was increased significantly in TA group(20mg/kg/d,40 mg and 60mg/kg/d).There was significant difference between TA group and ISO groups(P<0.05).It is found that the effect of TA has a dose dependent.2 Effect of TA on heart weight?left ventricular weight?the ratios of heart weight to body weight and left ventricular weight to body in cardiac remodeling rats induced by ISO Given i.p.injections of ISO continuously 7 days,compared with control group,HW,LVW,HW/BW and LVW/BW in ISO group was increased significantly,and there was significant difference between the two groups(P<0.05).The myocardial hypertrophy parameters was decreased by treatment of TA(20,40 and 60mg/kg/d)for two weeks,there was significant difference between the TA groups and ISO group(P<0.05).3 Effect of TA on CSA and PVCA in cardiac remodeling rats induced by ISO Rat hearts shown by HE and VG staining were histopathologically examined by lightmicroscopy.Myocardial fiber longitudinal diameter and CSA increased significantly compared with control group,there was significant difference(P<0.01)showed by HE staining.Normal cardiac myocytes in the control group showed by VG staining that myocardial fibers are yellow and collagen is red.Myocardial fibers is abundant in myocardial normal control group;interstitial CVF and and perivascular PVCA is less.Myocardial collagen fiber,interstitial CVF and perivascular PVCA in ISO group were increased significantly,Myocardial fibers was decreased;compared with control group,there was significant difference(P<0.01).By treatment of TA(20,40 and 60mg/kg/d)for two weeks,myocardial collagen fiber,interstitial CVF and and perivascular PVCA in ISO group were decreased significantly,myocardial fibers was increased;compared with ISO group,there was significant difference(P<0.01).4 Effect of TA on levels of hydroxyproline(Hyp)in myocardial tissue and Brain Natriuretic Peptide(BNP)in serum Compared with the control group,ISO group of Hyp content in myocardial tissues of rats increased significantly(P<0.01).After treatment by TA(20,40,60 mg/kg)experiment 2 weeks,Hyp content in myocardial tissues of rats in the TA group of decreased significantly,compared with ISO group,the differences were statistically significant(P<0.05,P<0.01).Give TA(20mg/kg)2 weeks,BNP content in rats serum has a tendency to reduce.Compared with ISO group,there was not statistically significant difference(P>0.05).After treatment by TA(40,60mg/kg)2 weeks,BNP content in serum of rats was decreased significantly,compared with ISO group,the differences were statistically significant(P<0.05,P<0.01).5 Effects of TA on Bax/Bcl-2 ratio,levels of caspase-3 and NF-k B in myocardium Western blotting analysis revealed significant increases in the ratio of Bax/Bcl-2 and levels of caspase-3 and NF-?B in ISO-treated rats,compared with ISO group,there was statistically significant difference(P>0.05).However,given TA(20 mg/kg,40,60 mg/kg)2 weeks,the ratio of Bax/Bcl-2and levels of caspase-3 and NF-?B were decreased,TA(20,40 and 60mg/kg/d)treatment markedly suppressed almost all of the Cardiac remodeling induced by ISO in rats.Compared with ISO group,the differences were statistically significant(P< 0.05,P <0.01).Conclusions: Cardioprotective effect of TA which may possibly be due to improve parameters of heart hemodynamics,decrease parameters of cardiac hypertrophy,myocardial morphologic change,surpress myocardial fibrosis,decrease content of Hyp and BNP.Mechanisms may be related to downregulation Bax/Bcl-2 and level of Caspase-3 and NF-?B.Part2 Effect of tannic acid on oxidative stress,inflammatory changes and dyslipidemias in ISO induced cardiac remodeling ratsObjective: The effects of tannic acide on oxidative stress,inflammatory changes and dyslipidemias were assessed in isoproterenol(ISO)-induced cardiac remodeling in rats.Methods: Methods of subgroup and administration are same with “the second part”.Results:1 Effect of TA on activity of SOD,GSH-Px and concentration of CAT,MDA in cardiac remodeling rats A singnificant elevation in MDA and a decline in CAT level were observed in heart tissues of ISO-treated rats after 1 weeks,compared with control rats(P<0.01).Moreover,ISO-treated rats 1 weeks showed considerably lower activities of SOD and GSH-Px in heart tissues in comparison with control rats(P<0.05,P<0.01).Notably,treatment with TA(20,40,60 mg/kg),level of MDA was decreased and CAT was increased comparison with ISO group(P<0.01).After treatment by TA(20,40 mg,60mg/kg/d)for 2 weeks,activities of SOD had no higher in L-TA(20 mg/kg)(P>0.05),but considerably higher in M-TA(40 mg/kg)(P<0.05),the highest in H-TA(60 mg/kg)(P<0.01)in heart tissues.Activity of had GSH-Px in heart tissues were considerably increased in every dose in comparison with control rats(P<0.01).2 Effect of TA on IL-1? and TNF-?,c-fos,c-jun protein expressions in heart Expression level of inflammatory factors such as IL-1?,TNF-?,c-fos,c-jun is very low in normal cells.Expression was significantly related increase and cell damage and inflammation.Expression level of IL-1?,TNF-?,c-fos,c-jun was very considerably higher in rats ventricular tissue of ISO group(P<0.01).After treatment by TA(20,40 mg,60mg/kg/d)2 weeks,IL-1,TNF-?,IL-1,c-fos,c-jun expressed group significantly decreased,comparison with ISO control with statistical significance(P<0.01).3 The effect of TA on CRP in rats of cardiac remodeling induced by ISO in serum CPR concentration of the control group was low,while CPR concentration of the ISO group is obviously increased,comparison with statistical significance(P<0.01).CPR concentration of the TA group(20,40 mg and 60mg/kg/d)was decreased,there was statistical significance comparison with the ISO group(P<0.05,P<0.01).Study also showed that there was a dose dependent on reducing concentrations of CPR by TA.4 The effect of TA on serum lipid metabolism in rats cardiac remodeling induced by ISO in serum Rats treated with ISO showed a significant increase(P<0.01)in these levels of TC,LDL,and VLDL levels and also the levels of triglycerides,free fatty acids,and phospholipids with the levels of HDL being an exception where there was a significant decrease.The administration of TA for 2 weeks,levels of HDL being an exception where there was a significant decrease significantly decreased the levels of cholesterol,lipoproteins,and lipids with subsequent increase in the levels of HDL cholesterol at close to control levels in the treatment groups(20,40 and 60mg/kg/d)as compared to group ISO(P<0.05,P<0.01).TA at a dose of 50 mg/kg showed minor changes in TC,HDL,VLDL,TG and free fatty acids and phospholipids but they were not statistically significant(P>0.05).Conclusions:Cardioprotective effect of TA which may possibly be due to suppress oxidative stress level,decrease expression of inflammatory factors,regulate lipids metabolism.The mechanisms may be attributed to its ability to downregulate expression of IL-1?,TNF-?,c-fos,c-jun.Part3 The protective effects and potential mechanism of TA on ISO-induced acute myocardial injuryObjective:To establish animal model of ISO-induced acute myocardial injury.Research the protective effect and potential mechanism of TA on ISO-induced acute myocardial injury in rats.Methods: After one week of acclimation,all rats were randomly divided into five groups of 10 animals per group: control,ISO,verapamil(VER),low-dose TA(L-TA,20mg/kg/day),and high-dose TA(H-TA,40mg/kg/day)groups.All drugs were given as follows.Control and ISO groups were injected intraperitoneally(i.p.)with saline(0.1m L/kg/day).Rats of the VER group were given i.p.injections of VER(2mg/kg/day).The L-TA,H-TA groups were intragastric administration of TA at 20,40 mg/kg/day for one week,respectively.Rats were pretreated for 7 days and then intoxicated with ISO(8mg/kg)by intraperitoneal(ip)injection.The control group animals received intraperitoneal(ip)injection with isovolumic saline.Results:1 Effect of TA on parameters of ECG patterns and heart hemodynamics in acute myocardial injury rats induced by ISO Analysis of ECG patterns and heart hemodynamics revealed a significant increase in ST-segment elevation,heart rate,LVEDP and ±dp/dtmax in ISO group,compared to the control group(P<0.01).However,pretreatment of animals with TA and VER caused restoration of both parameters to nearly normal levels,compared to group ISO,there were statistically significant(P<0.05,P<0.01).Before the injection of ISO,the group pretreated with TA shows no significant difference from the control and ISO groups.2 Effect of TA on cardiac marker enzymes and endothelial function in rats of ISO-induced myocardial injury Changes of CK,CK-MB,LDH,ET-1 and NO levels in serum of control and experimental rats are shown.The values of myocardial enzymes was significantly higher(P<0.01,CK elevated by 53.61%,CK-MB elevated by79.05% and LDH elevated by 42.56%)in the group ISO when compared to control.The values of myocardial enzymes showed a significant(P<0.01)reduction in TA and VER when compared to the ISO group.The level of ET-1was a significant increased 40.84%(P<0.01),while there were significantly to normal levels by TA and VER pretreatment compared to ISO values.On the contrary there was decreased by 62.94 % in the level of NO in ISO group(P<0.01),there was increased the level of NO by TA and VER pretreatment.3 Effect of TA on histopathological changes in rats of ISO-induced myocardial acute injury Rat hearts were histopathologically examined by light microscopy.Normal cardiac myocytes in the control group were observed without necrosis,edema or inflammation,whereas those in the ISO group showed a significant number of wavy fibers,myofiber loss,extensive necrosis,infiltration of inflammatory cells,marked myocellular edema and myocyte vacuolization.In L-TA,H-TA and VER groups,the extent of inflammatory cell infiltration,myocardial tissue necrosis or edema was much lower as compared to the ISO group.However,the progressive vacuolization of myocytes was attenuated by TA.4 Effect of TA on activities of SOD,GSH-Px and concentration of MDA,CAT in acute myocardial injury rats As depicted in Fig.4A–D,a significant elevation in MDA by 112.41% and a decline in CAT level by 48.87%(P<0.01)were observed in heart tissues of ISO-treated rats compared with control rats.Moreover,ISO-treated rats showed considerably lower activities of SOD(declined by 61.77%)and GSH-Px(declined by 51.70%)in heart tissues in comparison with control rats.Notably,pretreatment with TA returned these altered parameters to normal levels.5 Effect of TA on c-fos,c-jun,IL-1?,TNF-?,Bax/Bcl-2,cleaved-caspase-3and-9 protein expressions in ISO-induced myocardial injuryheart sections IL-1?,TNF-?,c-fos,c-jun,cleaved-caspase-3and-9,which are predominant-ly associated with cell injury and apoptosis,were expressed at low levels in the control group(Fig.5,Fig.6 and Fig.7),whereas after ISO injection,positive staining of the molecules above was extensive and greatly increased in the surrounding cardiac muscle cells compared with that in the control group(P<0.01).By contrast,concurrent administration of ISO at either the low dose or high dose TA evidentlydiminished the expression of all these aforementioned parameters(P<0.01).Conclusions: TA had beneficial effect on a significant decrease in ST-segment elevation and heart hemodynamics,values of myocardial enzymes and suppress oxidative stress level,in acute myocardial injury rats induced by ISO.The mechanisms may be attributed to its ability to downregulate expression of c-fos,c-jun,IL-1?,TNF-?,Bax/Bcl-2,caspase-3 and-9 protein and to decrease ET-1,increase NO,improve endothelial function. |
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