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正加速度重复暴露后大鼠心室肌缝隙连接蛋白43表达及分布的改变

周瑛, 孙喜庆, 王冰, 耿捷, 王永春

第四军医大学航空航天医学系航空航天生物动力学教研室,航空航天医学教育部重点实验室.陕西,西安 710032

摘要

该文旨在探讨不同水平的一周重复多次正加速度(+Gz)暴露后大鼠心室肌缝隙连接蛋白43 (connexin 43, Cx43)表达及其分布的改变。36只雄性Sprague--Dawley大鼠随机分为对照组、+6Gz组和+10Gz组，每组12只。+Gz组大鼠分别暴露于+6Gz和+10Gz各3 min，1次/d，共1周，分别于末次暴露后即刻、1 d、3 d、7 d (各3只)取心室肌作免疫组织化学染色和Western blot分析，检测Cx43的表达和分布。免疫组织化学结果显示，+Gz重复暴露可引起大鼠心室肌Cx43分布方式明显紊乱，在心肌细胞侧-侧连接处的表达明显增加，在心肌细胞端-端连接处的表达减少。Western Blot结果显示，+6Gz组与+10Gz组的Cx43蛋白表达量于末次暴露后即刻、1 d、3 d、7 d与对照组相应时刻相比均明显减少({sl P}<0.001)，以暴露后即刻减少最为明显，且随着+Gz暴露时间的延长，表达逐渐恢复，但在暴露后7 d，两组的Cx43表达量仍未恢复至对照组水平。Cx43蛋白表达的上述改变在+10Gz组比+6Gz组更为显著。以上结果提示+Gz重复暴露可引起大鼠心室肌Cx43表达量的一过性减少，分布方式明显紊乱，这种改变很可能是+Gz致心律失常发生的重要原因之一。

关键词： 加速度; 心肌; 连接蛋白43; 免疫组织化学; 蛋白印迹法

Expression and distribution of connexin 43 in myocardium of rats after repeated positive acceleration exposures

Zhou Ying, Sun Xiqing, Wang Bing, Geng Jie, Wang Yongchun

Key Laboratory of Aerospace Medicine,Ministry of Education,Faculty of Aerospace Medicine,the Fourth Military Medical University.Xi'an 710032,Shaanxi

Abstract

The present study was designed to observe the expression and distribution of connexin43 (Cx43) in myocardium of rats after repeated positive acceleration (+Gz) exposures. Thirty six male Sprague-Dawley rats were randomly divided into 3 groups (n=12): control group, +6Gz group and +10Gz group. The rats in +6Gz group were exposed to +6Gz for 3 min daily, 1 week, while rats of +10Gz group were subjected to +10Gz for 3 min daily, 1 week. All animals were anaesthetized and necropsied immediately, 1 d, 3 d and 7 d after the last exposure. The expression and distribution of Cx43 in the ventricles of hearts were examined by immunohistochemistry and Western blot analysis. The immunohistochemistry results showed that in control group abundant expression of Cx43 was observed with intense punctate labelling confined to the intercalated disks between cardiomyocytes. After +Gz exposure, there was a loss of the immunoreactivity of Cx43, which was consistent with Western blot results, and distribution changes of Cx43, with an increase in side-side Cx43 and a decrease in end-end Cx43. Western blot analysis revealed that Cx43 expression was modified in response to different exposure program and different recovery time. The protein expressions of Cx43 were lower at 4 time points after exposure in either +6Gz or +10Gz groups compared with that in the control group (P<0.001). Densitometry analysis of immunoblots revealed a decrease in the total amount of Cx43 signals immediate after exposure while an increase during the recovery time. After 7-day recovery, the amounts of Cx43 of two exposure groups were still lower than that in the control group (P<0.001). The decrease of Cx43 expression in +10Gz group was more significant that in +6Gz group. The results demonstrated that the decrease and distribution disturbance of Cx43 in the ventricle of rats after repeated +Gz exposures could be recovered. These findings facilitate our understanding of the mechanisms of arrhythmias caused by +Gz and provide new protective measures.

Key words: acceleration;Myocardium;connexin 43;Immunohistochemistry;Western blot

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引用本文：

周瑛, 孙喜庆, 王冰, 耿捷, 王永春. 正加速度重复暴露后大鼠心室肌缝隙连接蛋白43表达及分布的改变[J]. 生理学报 2008; 60 (3): 320-326.

Zhou Ying, Sun Xiqing, Wang Bing, Geng Jie, Wang Yongchun. Expression and distribution of connexin 43 in myocardium of rats after repeated positive acceleration exposures. Acta Physiol Sin 2008; 60 (3): 320-326 (in Chinese with English abstract).