The Protective Effects Of Pioglitazone On Cadiocyte Membrane In Hyperlipemia Rats Subjected To Myocardial Ischemia And Reperfusion

Objective:Pioglitazone(PIO),a kind of peroxisome proliferators-activated receptor (PPAR)γagonist,exerts anti-oxidation and attenuate hyperlipemia effects.However,The protective effects of pioglitazone on cadiocyte membrane in hyperlipemia(HL)rats subjected to myocardial ischemia and reperfusion remain largely unknown.The aim of this study was to test the feasibility of the protective effects,which was hoped that the problem will be resolved with our proposed method.Using a diet-induced hyperlipemia rats subjected to myocardial ischemia and reperfusion,we examine the effects of PIO on the content of cholesterol, phospholipid and cadiocyte membrane fluidity.Methods:Male Wistar rats were fed with normal or high cholesterol diets for 8 weeks.4 weeks after being fed with a high cholesterol diet,HC rats were randomized to receive vehicle or pioglitazone during the remaining 4 weeks.At the end of the 8 weeks,the index of the cardiomyocyte or blood was detected.①The cadiocyte membrane of the model rat was extracted by low temperature and high speed centrifugation.The ATPase activity was determined to identify cadiocyte membrane.The content of cholesterol(C),phospholipids(P), and C/P of the cadiocyte membrane were respectively determined.②The cadiocyte cell were separated by the enzymic method.The cadiocyte membrane fluidity was determined by DPH marking method.③the content of MDA in the serum,SOD activity and GPX activity were respectively determined.④The level of TC,TG,HDL-C in the serum was respectively determined by Cholesterol Kit,Triglycerides Kit,and HDL-Cholesterol Kit.Results:1.To set up HLrats model:Compared with rats fed with a normal diet,HL rats had increased level of TC(total cholesterol),TG(triglycerides)and HDL-C(high density lipoprotein cholesterol)in the serum.2.The myocardial cell membrane fluidity is lower obviously in the HL rats than that in the normal diet rats:The degree of fluorescence polarization is a main index sign which judges the cell membrane fluidity.Compared with the normal diet rats,HL rats had increased degree of fluorescence polarization of(0.240±0.049 vs.0.336±0.074,P＜0.01).The C/P, which is presenting the inverse ratio relation with the cell membrane fluidity,of myocardial cell membrane in the HL rats is 0.44±0.038,which was significantly higher than that in the rats fed with normal diet(0.33±0.033,P＜0.01),indicating that s decreased fluidity of membrane occurred in diet induced HL myocardial cell.3.In addition to decrease the TC,TG and increase antioxidation,the PIO could also increase the fluidity of the HL rats' myocardial cell membrane.3.1 PIO improves plasma lipid profiles:Treatment with PIO in HL rats decreased lipid profile in this diet-induced hyperlipemic model as evidenced by decreased TC(from 3.61±1.25 mmol/L to 1.75±0.89 mmol/L,P＜0.01)and TG(form 1.66±1.31 mmol/L to 0.64±0.19 mmol/ L,P＜0.01)in the serum of HL rats.3.2 PIO attenuated oxidative stress:Treatment with PIO in diet-induced rats attenuated oxidative stress as evidenced by decreased of MDA(from 5.69±0.62 nml/ml to 4.76±0.71 nml/ml,P＜0.05)in serum of HL rats;and increased GPX activity(from 25.76±1.94 U/ml to 29.60±2.61 U/ml,P＜0.05).3.3 PIO increased myocardial cell membrane fluidity in HL rats:The PIO could significantly decreased the specific value of C/P(0.40±0.036,P＜0.05),and decreased the degree of fluorescence polarization to 0.19±0.050(P＜0.05)in the HL rats myocardial cell membrane.Conclusion:Our results demonstrated that hyperlipemia induced lower membrance fluidity likely by increasing the ratio of cholesterol and phospholipids,which may be significance due to the cell membrane playing important roles in energy conversion,material transport,and cell signal transduction function.In addition,our results suggest that Pioglitazone,a PPARγagonist, may not only improve plasma lipid profiles,decrease oxidative stress associated with hyperlipemia as previously reported,but also protect the myocardial cell membrane fluidity form the cell injury induced by HL.