Pathological Study And Expression Of HCN4,Cx40 And Cx45 Of Sinus Nodes In Patients Of Sudden Cardiac Death And Its Significance

Objective:To observe the pathological change of sinus nodes in patients of sudden cardiac death and expression of hyperpolarization activated cyclic nucleotide gated cation channel 4 (HCN4),connexin Cx40 and connexin Cx45 and its significance.Method:Twenty-one cases of sudden cardiac death were used as experimental group, the control group consists of eighteen cases, including nine cases of traffic accident, four cases of heart rupture, three cases of liver rupture and two cases of spleen rupture. Routine paraffin embedding, HE staining and Masson's staining were performed, HCN4,and Cx40 and Cx45 expression in sinus nodes were studied with immunohistochemical staining. Using Mann-Whitney Rank-Sum Test and Spearman's rank correlation for statistical analysis.Results:Pathological observation of sinus node Cardiac conduction system disease are mainly bleeding, inflammation, fatty infiltration, fibrosis, arterial stenosis, neurological diseases, cancer and developmental abnormalities. In this experiment, the sinus node the major pathologic changes include fatty infiltration, fibrosis, arterial stenosis, inflammation.Expression of HCN4 in Sinus node:HCN4 is widely expressed in conduction system of heart in this experiment, HCN4 expression in the adult sinus node, non-homogeneous distribution in the cytoplasm and cell membrane, in SCD group, positive staining for the brown coarse grains, in control group, expressed as small brown grains and the distribution of small and sparse. statistical comparison of SCD group and the control group, the results of the expression of SCD group was significantly higher, statistically significant(P=0.015 <0.01).Expression of Cx45 in Sinus node:Cx45 expression in control group, positive staining for the brown coarse grains, non-homogeneous distribution in the cytoplasm and cell membrane;in SCD group, positive staining for Buffy granules, the distribution same to the control group, statistically significant (P=0.008<0.01).Expression of Cx40 in Sinus node:Cx40 expression in sinus node was small in the control group, the positive expression was the small particles and non-homogeneous distribution in the cytoplasm and cell membrane, mostly parallel for cell long axis, there was micro or no expression Cx40, light yellow color, the distribution same to control group.he results of the SCD group expression significantly reduced, statistically significant (P= 0.001＜0.05). Spearman's rank correlation was used in analyzing correlation between the SCD group and control group. In SCD group, n=14, r=0.5514,P <0.05. In control group, n=17, r=0.5619, Expression of Cx40 and Cx45 was associated(P<0.05).Conclusion:Morphologic change in cardiac conduction system is an important cause of sudden cardiac death. Increased expression of HCN4 and decreased expression of Cx40and Cx45 are significantly correlated with the incidence of sudden death.