Relationship between β_3-adrenoceptor expression and left ventricular hypertrophy

Objective To investigate the relationship between β_3-adrenoceptor expression and left ventricular hypertrophy (LVH) in rats.Methods Forty male Wistar rats were randomly divided into sham-operated group(sham group) and study group,twenty rats in each group.The left ventricular hypertrophy model was established by abdominal aortic constriction.Echocardiographic parameters,left ventricular mass index (LVMI) and the level of β_3-adrenoceptor expression were analyzed in the two groups four weeks and eight weeks after operation.Results The left ventricular posterior wall thickness at end diastole (LVPWTD) and interventricular septum thickness at end diastole(IVSTD) in the study group were thicker than in the sham group (P0.05),but the left ventrieular end-diastolic dimension (LVEDD) was similar between the two groups (P0.05) four weeks after operation.In the study group,LVPWTD and IVSTD were significantly increased (P0.01),and LVEDD was significantly decreased (P0.01) eight weeks after operation compared with those four weeks after operation (P0.01).The LVMI in the study group was higher than in the sham group(P0.01) after operation.In the study group,the LVMI was significantly increased (P0.01) eight weeks after operation compared with those four weeks after operation.The level of β_3-adrenoceptor mRNA expression in left ventricle in the study group was significantly higher eight weeks after operation compared with those four weeks after operation (1.240 ±0.036 vs.1.182±0.029,P0.01),whereas it remained unchanged in the sham group.In each group,there was a significant correlation between the level of β_3-adrenoceptor expression and the LVMI.Conclusion There is a significant increase in the β_3-adrenoceptor expression in the hypertrophic ventricles in rats.The increase in β_3-adrenoceptor expression is related to the severity of ventricular hypertrophy.