AIM To study the expressions of the coxsackievirus-adenovirus receptor and connexin45 in node tissues of rats with atrioventricular block and to understand the precise pathogenesis accounting for ischemia-induced atrioventricular block and electrophysiological behavior of the AV node.
METHODS SD rats were randomly divided into two groups: an atrioventricular block model group (n = 12) and a sham operation group (SH) (n = 6). The model group was divided into an AVB 2 h group (n = 6) and an AVB 4h group (n = 6), according to the time of atrioventricular block. The atrioventricular block rat model was induced by ligating the right coronary artery. The model group and the SH group were treated at 2 h and 4h after establishment of the model. Serial sections from the node area were obtained. Immunofluorescence analyses were performed to evaluate the locations and expressions of CAR and Cx45 in the node area. The expressions of CAR and Cx45 were quantitatively analyzed by Western blot.
RESULTS Immunofluorescence staining showed that CAR and Cx45 were mainly located in the atrioventricular node and expressions of CAR and Cx45 increased in the model group (AVB 2 h and AVB 4 h group) compared with those in the sham operation group. Western blot showed that the expressions of CAR and Cx45 in the AVB 2 h group were significantly higher than those in the sham operation group (P< 0.05). In the AVB 4h group, the expressions of CAR and Cx45 increased compared with those in the sham operation group, but there was no significant difference. Protein expression correlation analysis of CAR and Cx45 indicated that there was a significant positive correlation between CAR and Cx45 expressions (P< 0.05).
CONCLUSION The expressions of CAR and Cx45 protein increase in the node area of atrioventricular block rats after acute myocardial infarction and there is a significant positive correlation between CAR and Cx45 protein expressions.
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