低温联合七氟醚对兔心肌缝隙连接蛋白connexin43表达的影响

Effects of hypothermia combined with sevoflurane on expression of myocardial gap junction protein connexin 43 in isolated rabbit hearts

目的 探讨低温联合七氟醚对兔心室肌缝隙连接蛋白connexin43（Cx43）表达的影响.方法 成年家兔,体重1.5 ～2.0 kg,雌雄不拘,成功制备Langendorff模型的40个心脏,采用随机数字表法,将其分为4组（n=10）,平衡灌注15 min时,正常对照组（C组）继续灌注37℃K-H液；七氟醚组（S组）灌注2.4％七氟醚饱和的37℃K-H液；低温组（H组）灌注30℃ K-H液；低温联合七氟醚组（HS组）灌注2.4％七氟醚饱和的30℃K-H液,于灌注30 min时取左心室前壁组织,分别采用免疫组化及Westem blot法检测心肌细胞Cx43表达情况.结果 与C组比较,H组心肌细胞Cx43表达下调（P＜0.05）,S组和HS组心肌细胞Cx43表达差异无统计学意义（P＞0.05）,S组和HS组Cx43主要表达细胞两端的闰盘处,H组Cx43在闰盘处分布较少,而在侧侧连接处增多.结论 七氟醚可抑制低温诱导兔心肌Cx43表达下调和分布紊乱,可能是七氟醚抑制低温诱发心律失常发生的机制.

Objective To investigate the effects of hypothermia combined with sevoflurane on expression of myocardial gap junction protein connexin 43 （Cx43） in isolated rabbit hearts.Methods Healthy adult rabbits of both sexes,weighing 1.5-2.0 kg,were sacrificed after anesthetization.The hearts were rapidly excised and perfused in a langendorff apparatus with K-H solution saturated with 95％ O2-5％ CO2 at 37 ℃ in a langendorff apparatus.Forty isolated hearts were randomly divided into 4 groups （n =10 each）：control group （group C）,hypothermia group （group H） and hypothermia combined with sevoflurane group （group HS）.At 15 min of equilibration,the perfusion with K-H solution was continued at 37 ℃ in group C,K-H solution saturated with 2.4％ sevoflurane was perfused at 37 ℃ in group S,K-H solution was perfused at 30 ℃ in group H,and K-H solution saturated with 2.4％ sevoflurane was perfused at 30 ℃ in group HS.At 30 min of perfusion,myocardial specimens were obtained from the anterior wall of the left ventricle for detection of the expression of Cx43 in myocardial cells （by immunohistochemistry and Western blot）.Results Compared with group C,Cx43 expression was downregualted in group H （P ＜ 0.05）,and no significant change was found in Cx43 expression in S and HS groups （P ＞ 0.05）.Cx43 levels distributed mainly in the intercalated disc in S and HS groups,and in H group the distribution of Cx43 levels in the intercalated disc was less,but the percentages of lateralized Cx43 were increased.Conclusion Sevofurane can inhibit hypothermia-induced down-regulation and distribution disturbance of myocardial Cx43 expression,which may be the mechanism by which sevofurane inhibits hypothermia-induced arrhythmia.