Effects of Tongxinluo on connexin 43 remodeling and ventricular arrhythmia after myocardial infarction in rats

AIM: To determine the effects of Tongxinluo( TXL) on connexin 43( Cx43) remodeling and ventricular arrhythmia( VA) after myocardial infarction( MI) in rats. METHODS: Male SD rats were randomly divided into sham-operated( sham) group( n = 25) and operation group( n = 75). The left anterior descending( LAD) was ligated in operated group,while the rats in sham group only underwent pericardiotomy. The rats in operation group which survived for3 d after operation were randomly assigned to TXL group and MI group. The rats in TXL group was administrated with TXL( 2 g·kg-1·d-1,intragastric administration) for 4 weeks,while normal saline was applied to the rats in sham group and MI group. The levels of interleukin-1β( IL-1β) and endothelin-1( ET-1) in the tissue from the border zone were measured by ELISA after treatment. The distribution and the mRNA and protein expression of Cx43 were detected by immunohistochemical staining,RT-PCR and Western blotting,respectively. The burst pacing was used to induce ventricular arrhythmia( VA). RESULTS: Compared with sham group,the levels of IL-1β and ET-1 and the incidence of VA were significantly increased,while the mRNA and protein expression of Cx43 was markedly reduced with irregular distribution in MI group( P 0. 05). Compared with MI group,the levels of IL-1β and ET-1 and the incidence of VA were significantly reduced,while the expression of Cx43 at mRNA and protein levels was markedly increased with augmented linear distribution in the myocardial cell intercalated disc in TXL group( P 0. 05). CONCLUSION: TXL reduces the incidence of VA after MI via inhibiting the Cx43 remodeling.