摘要
目的 :观察家兔快速心房起搏所致的心房肌间隙连接蛋白 4 0 (Connexin 4 0 ,Cx4 0 )的改变及粉防己碱 (tetrandrine)的防治效果 .方法 :32只家兔随机分为 3组 :正常对照组 (n=8) ,快速心房起搏组 (n =1 2 )、粉防己碱组 (n =1 2 ) .经颈内静脉将电极置入右心房 ,后两组以 6 0 0次 /min行快速心房起搏 ,同时粉防己碱组于快速起搏前 30min按每小时 30mg/kg静脉给药 ,另两组给等容量的生理盐水 .连续刺激 8h后开胸取右心耳组织 ,分别用生化方法检测心肌细胞内Na+ ,K+ 和Ca2 + 水平 ,用Westernblot检测Cx4 0含量 ,用透射电镜观察超微结构 .结果 :快速心房起搏组心肌细胞内Na +,Ca2 + 水平增加 ,而Cx4 0含量降低 (P <0 .0 1 ) ,心房肌细胞损伤的超微结构变化明显 .粉防己碱组心肌细胞内Na+ ,Ca2 + 水平降低 ,Cx4 0的降解和心房肌细胞损伤的超微结构变化减轻 .结论 :钙超载至少部分参与了持续快速心房起搏引起的Cx4 0降解 .粉防己碱能防止快速心房起搏引起的Cx4 0的降解 。
AIM: To observe the change of connexin (Cx40) level in the rabbit atria by rapid pacing and the effect of tetrandrine on it. METHODS: Thirty two rabbits were randomly divided into 3 groups: Normal control group ( n =8), rapid atrial pacing group ( n =12), tetrandrine group ( n =12). The bipolar electrodes cather was inserted through internal jugular to the upper right atrium. Pacing were done in the latter two groups at the frequency of 600 times per minute.The infusion of tetrandrine was initiated 30 min before rapid pacing in the tetrandrine group. The other two groups were infused with the same volume of saline. the pacing duration was 16 h. The right atrial appendages were connected to perform the following examination. Na +, K + and Ca 2+ content of atrial tissues was assessed by biochemical technique. Cx40 level was examined by western blot. The electron microscopy was used to observe the ultrastructural alternation. RESULTS: Na + and Ca 2+ contents of rapid atrial pacing group were increased,but Cx40 level decreased markedly ( P <0.01) comparing with the normal control group. The ultrastructure of the atrial appendages was damaged. The degradation of Cx40 and Ca 2+ and Na + overload were attenuated in tetrandrine group. CONCLUSION: Degradation of Cx40 is at least in part mediated by an increased calcium influx in the atrial cells during prolonged rapid atrial pacing. Tetrandrine can prevent Cx40 degradation and tachycardia induced ultrastructural damage by inhibiting Ca 2+ influx.
出处
《第四军医大学学报》
CAS
北大核心
2004年第2期150-152,共3页
Journal of the Fourth Military Medical University