| Background:Myocardial apoptosis plays an important role in acute myocardial infarction(AMI)in the pathogenesis,inhibition of apoptosis has become an important method for the treatment of AMI.IL28RA is a subunit of Type Ⅲ interferon,has the effect of promoting apoptosis,which may be related to block the activation of JAK-STAT signaling pathway,including its downstream PI3K/AKT,MAPK signaling pathway,may also be related to promote autophagy of cells.PI3KCG gene is a catalytic subunit of PI3K I type,which have a close relationship of autophagy.In this study,cultured neonatal SD rat cardiomyocytes was investigated using siRNA transfection method,using RNA interference,the protective effects of interfering IL28RA gene were observed,and in rat model of acute myocardial infarction,using recombinant PI3KCG lentivirus vector,test whether the gene has a role in protecting PI3KCG acute myocardial infarction.Objective:To explore the protective effects of small interference RNA(siRNA)targeted interleukin 28 receptor alpha(IL28RA)gene that is regulate of IL28RA gene on the hypoxia reoxygenation cardiomyocytes injury.To study the protective effects of lentiviral expression vector containing human phosphatidylinositol 3-kinase p110 gamma(PLV-PI3KCG)on acute myocardial infarction.Methods:1.A complex was designed and synthesized,which consisted of three pairs of siRNA(siRNA-6158,siRNA-6160,siRNA-6162)interfering IL28RA gene expression.Liposome transfection method was used to transfect the siRNA into primary neonatal rat cardiomyocytes.The cells were divided into six groups as the normal control group,hypoxia and reoxygenation group(H/R group),H/R group+negative control transfection group,H/R +siRNA-6158 transfection group,H/R +siRNA-6160 transfection group,and H/R +siRNA-6162 transfection group.The cells survival rate and lactate dehydrogenase(LDH)level in the supernatant were detected.The appropriate transfection concentration was explored.The IL28RA,PI3K,TGF-β,BCL-2 and BAX protein expression was observed in the H/R process by using western blot method.2.Through the method of ligaturing left anterior descending coronary artery in rats,the model of acute myocardial infarction was established,and viral vectors containing PLV-PI3KCG were injected at the edge of the infarct zone.The experiment was divided randomly into four groups(n=8):(1)sham-operated group(Sham group);(2)acute myocardial infarction group(AMI group);(3)acute myocardial infarction plus empty vector(AMI + E group);and(4)acute myocardial infarction plus PLV-PI3KCG group(AMI + PLV-PI3KCG group).Structural and functional changes in rat heart were observed by echocardiography after 10 days of normal feeding,and then the rats were killed for their heart specimens.Morphological changes of myocardial tissue were observed with HE staining.CD31 protein expression in the infarct region was observed with immunofluorescence.And the changes of PI3KCG,AKT,TGF-p,BAX,BCL-2,and Beclin-1 protein expressions were detected.Results:1.80nmol/L siRNA concentration that interfering IL28RA gene is the appropriate transfection concentration.Compared with H/R group,the LDH activity in the H/R+siRNA-6158 group and H/R +siRNA-6160 group were significantly decreased(P<0.05),the survival rate in the both groups were significantly increased(P<0.05)and the IL28RA protein in the both groups were significantly reduced,PI3KCG,TGF-βprotein expressionsand BCL-2/BAX ratio were increased(P<0.05).2.10 days after acute myocardial infarction surgery,as compared with Sham group,left ventricular end-diastolic diameter(LVEDd)expanded,left ventricular ejection fraction(LVEF)significantly decreased,myocardial in the infarction mortified severely,fibroblast proliferated significantly,accompanied by inflammatory cells infiltration,and CD31 expression in the infarct region decreased;PI3KCG,AKT,TGF-1P,and BCL-2 protein expressions significantly decreased(P<0.05),and BAX and Beclin-1 protein expressions significantly increased(P<0.05)in the AMI group and AMI+E group.Compared with AMI group and AMI+E group,left ventricular end-diastolic diameter(LVEDd)decreased,left ventricular ejection fraction(LVEF)significantly increased,myocardialnecrosis decreased,and CD31 expression increased in the infarct region;PI3KCG,AKT,TGF-P,and BCL-2 protein expressions significantly increased(P<0.05);BAX and Beclin-1 protein expressions significantly decreased(P<0.05)in the AMI + PLV-PI3KCG group.Interventricular septum diameter(IVSd)and left ventricular posterior wall diameter(LVPWd)of each group had no significant difference(P>0.05).Conclusions:1.Inhibiting IL28RA gene expression was expected to be an important method of protecting anoxic myocardial disease.2.PI3KCG gene has protective effects in the acute myocardial infarction injury by inhibiting apoptosis and autophagy in rats.3.siRNA interfering IL28RA gene expression could protect the cardiomyocytes from H/R injury by activating the PI3K/Akt signal pathway and inhibiting cardiomyocytes apoptosis and autophagy. |
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