The Expression And The Meaning Of Cx40 And PGP9.5 In The Myocardial Sleeves Of Pulmonary Veins In Human

Background and object: The mechanism of atrial fibrillation is not yet fully elucidated ,which involed in a number of factors. Recent studies have shown the close relationship between the myocardial sleeves of pulmonary veins (PV) and atrial fibrillation. The sleeve of pulmonary veins is defined as the myocardial tissue winding the root of pulmonary vein trunk. It is the key anatomic site in triggering the focal Af, playing a function of ectopic focus of excitation. The PV shows autorhythmicity in embryonal period, and the antigen expression of the sleeve of PV is same to the cardiac conduction system in the development process. The neuron-specific antigen PGP9.5 (protein gene product 9.5) is a kind of ancient conserved protein, and it is shown that the positive rate of the expression of PGP9.5 in the sinus node, the atrioventricular node, the His bundle, the left bundle branch, the right bundle branch and the Purkinje fiber is significantly higher than the nearby cardiac myocytes. Studies also show that atrial fibrillation can lead to cardiac electrophysiology changes, affect protein expression, induced histological changes, especialing the gap junctional protein expression changes and redistribution, the gap junction remodeling, which is shown to be related to the increasing stability of Af. This study evaluates the feature and the pathological significance of the expression and the distribution of the gap junctional protein 40 (Cx40) and PGP9.5 in the myocardial sleeves of pulmonary veins in normal adults and the patient of rheumatic atrial fibrillation.Method: The myocardial sleeve tissues of left superior pulmonary vein from 15 patients of rheumatic atrial fibrillation were taken when receiving valve replacement operation; those from 20 normal adults were taken fromsinus rhythm decease cases without heart diseases during autopsy. The expression of PGP9.5 and histological features were evaluated by HE staining and two-step immunohisto- chemistry; the expression and distribution of Cx40 was evaluated by Olympus BX41 fluorescence microscope.Result:1. HE staining demonstrated that there was an obvious fibrosis in myocardial sleeves of pulmonary veins. Hydropic and vacuolar degenerated cardiac myocytes presented in the myocardial sleeves of pulmonary veins in the sinus rhythm group, and lightly stained P-like cells were observed in the myocardial sleeves of pulmonary veins in six cases, emerged individually or in groups; none of P-like cells were observed in atrial fibrillation group.2. Immunohistochemistry showed that PGP9.5 positive specialized cardiac myocytes and nerve fiber presented in myocardial sleeves of pulmonary veins in 10 cases of sinus rhythm group and 1 case of atrial fibrillation group.3. By Olympus BX41 fluorescence microscope, we observed that Cx40 homogeneously distributed in the myocardial sleeves of pulmonary veins in 12 cases of sinus rhythm group, many of the intercalated disc between cells were end-to-end connectivity. The distribution of Cx40 of ydropic or vacuolar degenerated cardiac myocytes and specialized cardiac myocytes changed, the end-to-end connectivity reduced in the intercalated disc, but the side-to-side connectivity increased. The distribution pattern of Cx40 significantly changed in 10 cases of atrial fibrillation group, end-to-end connectivity reduced, but side-to-side connectivity increased significantly.Conclusion:1. The specialized cells of myocardial sleeves of pulmonary veins have the same antigen expression of PGP9.5 with the cardiac conduction system.2. The redistribution of Cx40 in the myocardial sleeves of pulmonary veins is possibly related to the pathogenesis and the sustain of rheumatic heart disease cases with atrial fibrillation.3. The redistribution of Cx40 in myocardial sleeves of pulmonary veins is possibly related to the edema or degeneration of cardiac myocytes and specialized cardiac myocytes.