RESUMO
Objective: To study the effects of acute cold stress on connexin43 (Cx43) protein expression with drug intervention, and cell to cell conduction with its mechanism in neonatal rats’ myocardial cells. Methods: The primary neonatal rats’ myocardial cell culture was conducted in 4 groups. Group① , the cells were normally cultured, Group②, the cells were cultured at 4℃, Group③, the cells were cultured at 0℃and Group④, the anti-arrhythmia peptide (AAP 10) was added in Group②and Group③. The apoptosis rate of myocardial cells was evaluated by lfow cytometry assay, mRNA and protein expressions of CX43 were examined by RT-PCR and Western blot analysis, and CX43 phosphorylation product (P-CX43) was detected. Results: Compared with normally cultured cells, the myocardial cell apoptosis rate was obviously increased by acute cold stress at 4℃and 0℃with time extension. The mRNA expression of Cx43 was decreased at varying degrees at 4℃and 0℃stimulation, the protein expression of Cx43 was decreased at varying degrees at 4℃and 0℃stimulation with time extension, and P-Cx43 level was decreased. While the APP 10 intervention may obviously elevate the protein levels of Cx43 and P-Cx43. Conclusion: Acute cold stress could reduce the protein expression of CX43 and P-CX43, while APP 10 intervention may elevate such expression and improve the cell to cell conduction in neonatal rats’ myocardial cells.