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Objective To observe the transmural distributed heterogeneity of the expression of connexin 43 (Cx43) in three layers of left ventricle myocardium, and explore the physiological mechanisms of malignant ventricular arrhythmia (MVA) in a rabbit model with chronic congestive heart failure (CHF). Methods Twenty four New Zealand white rabbits were randomly divided into sham operation group (n=12) and CHF group (n=12) which were established with traditional abdominal aorta constriction. After operation, all rabbits were fed under the same conditions for 8 weeks. The left ventricular end diastolic diameter (LVEDD), left ventricular end systolic diameter (LVESD), thickness of the ventricular septum (IVS), thickness of the left ventricular posterior wall (LVPW) and the left ventricular ejection fraction (LVEF) were compared by in vivo echocardiography; the parameters of systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and maximum velocity of left ventricle and maximum descending speed (±dp/dtmax) were assessed by haemodynamic measurements between the two groups. The histopathological changes of left ventricular myocardium were observed by optical microscopy. The subendocardial myocardium (Endo), middle myocardium (Mid) and subepicardial myocardium (Epi) of left ventricular were resected, and the expression levels of Cx43 protein (Cx43-pro) and mRNA (Cx43-Cq) in all the three layers were measured by Western blotting, RT-PCR and immunohistochemical methods. Results Compared with sham operation group, the SBP, DBP, MAP and ±dp/dtmax decreased significantly (P0.05). The expression levels of Cx43-pro and Cx43-Cq in all the three layers of myocardium decreased in CHF group than in Sham group (P |
