3, 3', 4', 5, 7-Pentamethylquercetin Suppressed Restenosis Of Vein Grafts And Reduced Ang Ⅱ-induced Ventricular Remodeling In Rats

Polyphenol compounds are very important active ingredient in plants for Chinesemedicine and medical food; they are plenty in many plants, vegetables, fruits and drinks.Polyphenolic compounds, like resveratrol (RES) and quercetin (QUE), have extensivepharmacological effects, such as blood pressure lowing, anti-oxidation, anti-lipidperoxidation, anti-repeffusion injury and anti-tumor and so on; which are highly concernedin the medicine kingdom. However, natural polyphenol compounds could be oxidatedeasily because of their many hydroxyls, thus impact the extraction, manufacture and storing.Their low bioavailability, short half-life and low effect-price rate obstacle the exploitationand utilization as well. Polymethoxylflavonoids are methylation derivatives frompolyphenolflavonoid, which have obvious pharmacokinetics characteristics andpharmacodynamics advantage. Because of no big progress on the extraction process,polymethoxylflavonoids are limited sourced, expensive, and hard to be researched.Therefore, we methylized quercetin and obtained high-purified and inexpensivePentamethylquercetin (PMQ), which overcame the bottleneck of PMQ source and made thein-depth pharmacological study of PMQ a reality.In the earlier studies, we found that PMQ reduced the oxidation injury of H₂O₂ onisolated neonatal rat myocardial cells; extenuated ischemia reperfusion injury in vivo and invitro heart; suppressed proliferation of cultured cardiac fibroblast induced by aldosterone;relaxed isolated vascular rings by endothelium-dependent and endothelium-independentmechanisms. All these suggest that the advantages of PMQ on cardiovascular systemdeserve to be investigated. The patients with coronary heart disease after accepted coronaryartery bypass grafting operation faced two fundamental problems: chronic ventricalremodeling and vein graft restenosis caused by neointima. We wondered if PMQ had anyeffect on this kind of disease. In this study, we investigated the effects of PMQ on cardiachypertrophy and fibrosis induced by Angâ…¡; the influences of PMQ on proliferation ofvascular smooth muscle cell induced by Angâ…¡; the impacts on intimal hyperplasia model of autologous vein graft in rat and the mechanisms. In addition, we improved the methodsof isolation of adult rat cardiomyocytes for culture and experiment, of patch clamp andanastomosis to institute vein graft model.Partâ… 3,3',4',5,7-Pentamethylquercetin reduces cardiachypertrophy and apoptosis in Angiotensinâ…¡-infused ratsObjective The hypothesis that pentamethylquercetin (PMQ) reduces cardiac hypertrophyand myocyte apoptosis was tested in Angiotensinâ…¡(Angâ…¡)-infused rats. Methods: Thirtyrats were randomly assigned to the 5 groups with 6 rats in each group: (1) control group:Saline gavage was performed daily for 21 days; (2) PMQ group: PMQ (50mg/kg) gavagewas performed daily for 21 days; (3) Angâ…¡group: Angâ…¡(288μg/kg·d) was daily injectedsubcutaneously from the 15th day; (4) PMQ+ Angâ…¡group: PMQ gavage and Angâ…¡injection were performed as the same as above; and (5) solvent+ Angâ…¡group: Vehiclegavage was performed daily for 21 days, Angâ…¡injection was performed as the same asabove. Blood pressure was monitored daily utilizing tail-cuff. After the rats wereeuthanized at 22st day, the heart weight index (HW/BW) and the left ventricular weightindex (LVW/BW) were calculated, and the expression of BNP mRNA was determined byreal time-PCR. Myocyte apoptosis was measured by TUNEL assay and the expression ofBax and Bcl-2 were determined by immunohistochemistry. Results: PMQ reduces bloodpressure and cardiac hypertrophy induced by Angâ…¡by decreasing the heart weight index,the left ventricular weight index and the expression of BNP mRNA; inhibits myocyteapoptosis by reducing the expression of Bax, Bax/Bcl-2. Conclusion: PMQ reducescardiac hypertrophy and myocyte apoptosis in Angâ…¡induced hypertension rats. Theresults suggest that PMQ may represent an attractive therapeutic approach to treat CHF. Partâ…¡3,3',4',5,7-Pentamethylquercetin reduces cardiacfibrosis in Angiotensinâ…¡-infused ratsObjective: To investigate the effect of PMQ on Angâ…¡induced cardiac fibrosis. Methods:Thirty rats were randomly assigned to the 5 groups, 6 each: (1) control group: Saline wasadministrated daily via gavage for 21 days; (2) PMQ group: PMQ (50mg/kg) wasadministrated daily via gavage for 21 days; (3) Angâ…¡group: Angâ…¡(288μg/kg·d) wasinjected subcutaneously daily from the 15th day; (4) PMQ+ Angâ…¡group: PMQ and Angâ…¡were administrated as above; and (5) solvent+ Angâ…¡group: Solvent and Angâ…¡wereadministrated as above. After the rats were euthanized on the 22nd day, the myocardialhydroxyproline content was measured, and the expression of collagenâ… and collagenâ…¢mRNA were determined by real time-PCR. Collagen volume fraction (CVF)â… andâ…¢were detected by immunohistochemistry, and CVFâ… /CVFâ…¢was calculated. Results:PMQ reduced cardiac fibrosis in Angâ…¡induced hypertension rats by decreasing themyocardial hydroxyproline content, downregulating the expression of collagen I andcollagenâ…¢mRNA, and decreasing CVFâ… , CVFâ… /CVFâ…¢. Conclusion: PMQ couldreduce cardiac fibrosis.Partâ…¢3,3',4',5,7-Pentamethylquercetin downregulatesexpression of NADPH oxidase mRNA inAngiotensinâ…¡-infused ratsObjective: To investigate the mechanism of anti-ventricular remodelingof PMQ on Angâ…¡-infused rats. Methods: Thirty rats were randomly assigned to the 5 groups, 6 each: (1) control group: Saline was administrated daily via gavage for 21 days; (2) PMQ group:PMQ (50mg/kg) was administrated daily via gavage for 21 days; (3) Angâ…¡group: Angâ…¡(288μg／kg·d) was injected subcutaneously daily from the 15th day; (4) PMQ+ Angâ…¡group: PMQ and Angâ…¡were administrated as above; and (5) solvent+ Angâ…¡group:Solvent and Angâ…¡were administrated as above. After the rats were euthanized on the22nd day, the myocardial SOD activity and MDA content were measured, and theexpression of NADPH oxidase subunits Nox2 and p47^phox mRNA were determined by realtime-PCR. Results: PMQ exerted antioxidant function by increasing SOD activity anddecreasing MDA content and reducing the mRNA expression of NADPH oxidase subunitsNox2 and p47^phox. Conclusion: PMQ could reduce cardiac remodeling, which may resultfrom antioxidant functionPartâ…£3,3',4',5,7-Pentamethylquercetin suppresses theproliferation of VSMC and downregulates the mRNA expressionof NADPH oxidase induced by Angâ…¡Objective: To investigate the effect of PMQ on Angâ…¡induced proliferation of vascularsmooth muscle cells and its mechanism. Methods: The proliferation of vascular smoothmuscle cells were induced by Angâ…¡(0.1μmol/L, 24h) while PMQ was administrated atdifferent dosages(0.1, 0.3, 1, 3, 10 and 30μmol/L). Cell viability was detected by MTT;ROS was measured by DCFH-DA; and the expressions of NADPH oxidase subunits Noxl,p47^phox, and p22^phox mRNA were measured by real-time PCR. Results: PMQ suppressedthe cell viability and ROS of vascular smooth muscle cells induced by Angâ…¡. PMQ startedto demonstrated therapeutic effects from 0.3μmol/L, got the peak at 3μmol/L, and theeffects weakened from 30μmol/L to 10μmol/L. PMQ also downregulated the mRNA expressions of NADPH oxidase subunit Nox1, p47^phox and p22^phox induced by Angâ…¡.Conclusion: PMQ suppressed the proliferation of vascular smooth muscle cells induced byAngâ…¡, which maybe result from the anti-oxidation activity and mRNA expressiondownregulation of NADPH oxidase.Partâ…¤3,3',4',5,7-Pentamethylquercetin suppresses intimalhyperplasia of the vein graftObjective: To investigate the effect of PMQ on intimal hyperplasia of the vein grafts inrats. Methods: SD rats were randomly assigned to control group and PMQ group. Solventwas administrated daily in rats of control group via gavage, PMQ (12.5mg/kg, 25mg/kg,50mg/kg) was administrated daily in rats of PMQ group via gavage. The reversed jugularvein was implanted into the carotid artery. 4 weeks after operation, vein grafts wereharvested, and intimal hyperplasia of the vein grafts was assessed. Results: Compared withcontrol group, PMQ decreased intima/media area index and intima/media thickness index atthree dosages after implantation. The effects of 50mg/kg PMQ were weaker than PMQ at12.5mg/kg and 25mg/kg. Conclusion: PMQ could inhibit neointima hyperplasia of veingraft in rats.Supplementâ… Isolation of adult rat cardiomyocytesfor culture and experiment of patch clampObjective: To improve current enzymatic methods to isolate a high yield of high-quality adult rat cardiomyocytes for both culture and experiment of patch clamp. Methods:Calcium tolerant cardiomyocytes were isolated with collagenaseâ…¡by langendorff perfusion,Left and right ventricle myocytes were used respectively for culture with or without FBSand patch clamp. The currents of L-type calcium channels were recorded by patch clamp inthe entire cell mode. Results: With this method, we routinely obtained a highyield(3.7±0.6×10⁶/left ventricle) and high percentage(84.8±2.7%) of rod-shaped myocytes,most of which were clearly defined sarcomeric striations and quiescent state. A typicalcurrent of L-type calcium channel was recorded in the cardiomyocytes from right ventricle.Conclusion: this is a simple and reliable myocyte isolation method that greatly improvesthe yield, cell quality, and reproducibility of cardiomyocytes isolation and is suit to bothculture and patch clamp.Supplementâ…¡Two types of anastomosisto institute vein graft modelObjective: To compare two types of anastomosis in an animal model of intimal hyperplasiaof autologous vein graft in rats. Methods: SD rats were divided into two groups randomly.The external jugular veins were implanted into the external carotid of the same side withinterrupted suture and twice continuous suture respectively. Samples of tissues wereharvested at 4 weeks after operation. Situation of vein grafts were observed and tissuesections were analyzed by HE staining. Results: Compared with interrupted suture group,continuous suture had less time, less bleeding; but less graft patency. The intimalhyperplasia of two anastomosis methods had no obviously difference. Conclusion:Continuous suture has the advantages of costing less time and less bleeding, but it requiresmore skillful. It is no difference in the degree of intimal hyperplasia of autologous vein graft in rat.