Gap Junction Protein Cx45,Cx40 And TNF-a Expression And Function In The Infarcted Myocardium

Background and ObjectiveSudden death is increasing in the forensic test case,the study of sudden death have enough attention.Sudden Cardiac Death(SCD)in adult Death first.Acute Myocardial infarction(AMI)in malignant and fatal arrhythmia is one of the main cause of sudden cardiac death.AMI is coronary artery myocardial necrosis caused by acute,persistent ischemia hypoxia.In forensic,some sudden cardiac death,although through autopsy and histomorphology inspection system is still not clear the specific cause of death,so that further discovery and research of infarction myocardial markers of expression,change and the role of markers and malignant after myocardial infarction,the relationship between the lethal arrhythmia,can provide important clues and basis for diagnosis of forensic medicine.Gap junctions in the myocardial tissue protein(Cx)Connexin,a big peony card family,including many types,the molecular weight between 26 ~ 56 kd,it maintained the \ "electric coupling\" between different myocardial cell normal function,to participate in the formation of electrical excitation between myocardial cell,chemical signal transmission,maintain the normal operation of organ function.This experiment will by immunohistochemical method and PCR detection of gap junction protein 45(Connexin45,Cx45),gap junction protein 40(Connexin40,Cx40)and Tumor Necrosis Factor(Tumor Necrosis Factor,TNF-a)expression in the infarcted myocardium,and to study the effect of the three correlation,hopes for the cause of death in the diagnosis of sudden death of forensic science center source sex provide more scientific and accurate diagnostic method.Materials and methods1.Collect Da Lian Medical University clinical research center,2013-2015 autopsy specimens,choose the deaths due to sudden death,a total of 80 cases.This experiment will be divided into three groups: a,early myocardial ischemia group of 30 cases of sudden death;B,late myocardial infarction,sudden death group 30 cases;C,normal myocardial group 20 cases.Part experimental myocardial tissue samples fixed by 10% formaldehyde solution,paraffin embedding on each specimen,immunohistochemical staining;Part of the organization for autopsy after cryopreserved myocardial specimens,-80 ? low temperature preservation,used for extracting mRNA.2.This experiment mainly adopt the method of immunohistochemistry,through different groups are DAB staining method to detect myocardial tissues Cx45,Cx40 and TNF-a protein expression.3.The extraction of RNA in myocardial tissue,fresh using real-time quantitative PCR detection in groups of myocardial Cx45,Cx40 and TNF-a mRNA expression.4.By using SPSS13.0 statistical software analysis Cx45,Cx40 and the expression of TNF-a three and their correlation.Results1.The expression of myocardial Cx45 in three groupsCx45 expressed in three groups of myocardial tissue are all positive expression.Normal myocardium,myocardial ischemia early death,myocardial infarction,sudden death in late group in the positive expression rate of 80%,90% and 96.7% respectively.Two death Cx45 expression is higher than normal myocardial group,significant differences compared with normal cardiac muscle group,with statistical significance(P < 0.05).2.The expression of myocardial Cx40 in three groupsCx40 expressed in three groups of myocardial tissue are all positive.Normal myocardium,died early myocardial ischemia group and late positive expression rate of myocardial infarction,sudden death group were 85%,60% and 20% respectively.Two Cx40 expression in sudden death group than normal myocardial group decreased significantly,significant difference was statistically significant(P < 0.05).3.The expression of myocardial TNF-a in three groupsTNF-a in the sudden death of early myocardial ischemia group and late myocardial infarction,sudden death in the group is high expression of positive expression rate of 63.3%,83.3% respectively,and the late myocardial infarction,sudden death than the sudden death of early myocardial ischemia group express more and the normal myocardial expression positive rate of only 15.0%,compared with two death group there were significant differences(P < 0.05).4.Cx45,Cx40 and TNF-a mRNA expression in three groups of cardiac musclePCR results showed that protein Cx45,Cx40 protein and mRNA expression of TNF-a three consistent with their respective protein expression itself,in normal myocardium,died early myocardial ischemia group and late myocardial infarction,sudden death group there were significant differences in the expression,the difference was statistically significant(P < 0.01).5.Cx45,Cx40 and TNF-a correlation analysis in the three groups of cardiac muscleDied after statistical analysis found that: in the early myocardial ischemia group and late myocardial infarction,sudden death,Cx45 and TNF-a and mRNA expression increased,both were positively correlated,correlation coefficient R = 3.133,P < 0.01).Cx45 negative correlation and Cx40 and both mRNA expression,correlation coefficient R = 1.453,P < 0.01.Conclusion1.Cx45 and its mRNA in the sudden death of early myocardial ischemia group and late myocardial infarction,sudden death in myocardial cell cytoplasm expression levels higher than normal myocardium,it will be possible as auxiliary indexes in the diagnosis of sudden cardiac death.2.Cx40 and its mRNA in two death expression in myocardial tissue below the normal myocardial group,also can be used as one of the indicators of forensic medicine in the diagnosis of sudden cardiac death.3.TNF-a and its mRNA in the sudden death of early myocardial ischemia group and late expression of myocardial infarction,sudden death group is significantly higher than normal myocardium,myocardial ischemia and myocardial infarction,sudden death group than in the early late express more sudden death group,expression differences of the three groups,may be beneficial to the diagnosis of sudden cardiac death,and may,according to sudden death,myocardial tissue in the expression of TNF-a quantity of how many,on the severity of myocardial ischemia and infarction area of the size of the inferences.4.In the late early myocardial ischemic stroke and myocardial infarction,sudden death in myocardial tissue,Cx45,expression of TNF-a rise,Cx40 expression,the correlation of the three,will be for the cause of death in the diagnosis of sudden cardiac death is more accurate and more advantageous basis.