| ObjectiveTo observe the protective effects of Trimetazidine preprocessing on myocardial ischemia-reperfusion(I/R)injury in rats and the relationship with autophagy-related protein-microtubule-associated protein light chain 3 protein-?(LC3-?)and another autoclaved marker Sequestosome 1(p62/SQSTM1)(hereinafter referred to as p62)as well as to investigate the mechanism of action.Methods54 male Sprague-Dawley(SD)rats,with weight ranging from 230 g to 270 g,were build up the carrier model of myocardial ischemia-reperfusion injury(MIRI)in rats.The rats were anesthetized by intraperitoneal injection of 10%chloral hydrate solution,and tracheal intubated to assist respiration.At the left chest apex where the beat is most obvious,the chest is incised and the heart is exposed.The slipknot around the left anterior descending coronary artery is made through the myocardium with the 5?0 needle suture.Loosing the slipknot and restoring the blood supply of the left anterior descending coronary artery when tightening the suture causing the ischemia for 30 minutes.The rats in the sham operation group undergo the same procedures such as thoracotomy,except that the suture only pass through the myocardium without knotting and blocking the blood supply of the left anterior descending coronary artery.In order to observe the changes of LC3-? and p62 in I/R injury and normal myocardium,male SD rats were randomly divided into three groups in the study:sham group,myocardial ischemia-reperfusion model group(I/R group)and TMZ prepro-cessing on myocardial ischemia-reperfusion injury group(I/R+TMZ group).The rats in the I/R+TMZ group will be lavaged with TMZ solution(20 mg/kg d)and the Sham group and the I/R group will be lavaged with the same volume of saline.The rats in each group will be put to death at the moment of model completion,4 weeks later and 8 weeks later.The anterior wall myocardium of ventricle will be HE dyed to observe the organizational form.The RT-PCR is utilized to detect the expression of LC3-? and p62 mRNA,and the Western blotting to determine the levels of LC3-?and p62.Statistical analysis of the differences between the groups and the above phases.The differences beween each groups and time phases will be analysesed statistically.Results1.The effect of Trimetazidine on the expression of LC3-? and p62 in myocardium of ratsComparing in the group:The expression of LC3-11 and p62 mRNA and protein of the immediately in the cardiomyocytes of rats in I/R group were lower than those in 4 weeks(P<0.05),Compared with the 8 weeks,the expression of cardiomyocytes was increased at the 4th week after modeling(P<0.05);The expression of LC3-? and p62 mRNA and protein of the immediately in the cardiomyocytes of rats in I/R+TMZ group were lower than those in 4 weeks(P<0.05),Compared with the 8 weeks,the expression of cardiomyocytes was increased at the 4th week after modeling(P<0.05);Comparing between the groups:The expression of LC3-?,p62 mRNA and protein in each time phrases in I/R group are higher than that of sham group(P<0.05);Compared with I/R group,the expression level in the I/R+TMZ group is lower and decreased to level of sham group(P>0.05).There was no difference in the expression of LC3-?,p62 mRNA and protein between the I/R+TMZ group and the sham group(P>0.05).2.Effects of Trimetazidine on morphological changes of myocardial tissue in rats From the moment of model completion to 4 weeks later,the myocardial cell damage gradually exacerbated in I/R group:inflammatory infiltration of inflammatory cells,cell swelling and rupture and uneven nuclear staining and significant necrosis.The inflammatory changes in I/R+TMZ changes is quite the same as that of I/R group at the moment of model completion but damage mitigation found at the 8 weeks material drawing and there is no significant difference with the sham group.ConclusionThe intervention of Trimetazidine may protect the myocardium of ischemia-reperfusion injury in rats by regulating autophagy and keeps the effect for a certain time. |
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