跑台训练对大鼠心脏窦房结快激活I_(Kr)通道的影响  

Effects of treadmill exercise on the rapidly activating I_(Kr) channel of rat sinoatrial node

作　　者：薄冰[1] 

机构地区：[1]河南大学体育学院运动人体科学教研室,河南开封475000

出　　处：《基础医学与临床》2014年第11期1519-1523,共5页Basic and Clinical Medicine

基　　金：河南省教育厅科学技术重点研究项目(14A890008)

摘　　要：目的探讨大鼠两周力竭跑台训练对心脏窦房结快激活延迟整流钾离子(IKr)通道的影响。方法 SD大鼠分为对照组(C组)、一次力竭组(O组)、两周反复力竭组(R组),每组10只。C组大鼠不进行任何运动训练,O组大鼠在正常饲养两周后,进行1次跑台训练至力竭,R组每天进行1次跑台训练,训练时长为2周。训练组大鼠分别于运动后0及24 h取材,O组以O-0 h和O-24 h命名,R组以R-0 h和R-24 h命名。用实时荧光定量PCR和Western blot技术测定IKr通道亚基ERG1b mRNA及蛋白质表达,用全细胞膜片钳技术测定通道电流密度。结果 1)R-0 h及R-24 h组ERG1b mRNA及蛋白质表达明显低于C组及O-0 h组(P<0.01)。2)R-0 h及R-24 h组IKr通道电流密度分别为(0.89±0.03)p A/p F和(1.02±0.07)p A/p F,明显低于C组及O-0 h组的(1.81±0.12)p A/p F和(1.69±0.08)p A/p F(P<0.01)。结论反复力竭运动可引起大鼠心脏窦房结细胞膜IKr通道亚基ERG1b基因表达及电流密度减少,这可能成为运动引发窦房结功能障碍的离子通道机制之一。Objective The effects of two weeks exhaustive treadmill running on rapidly activating IKr channel of rat sinoatrial node.Methods SD rats were randomoly assigned into 5 groups as control groups （C group）,2 groups undergoing single exhaustive treadmill running （O group）,and 2 groups undergoing two weeks repeated treadmill running（R group）.After two weeks normal feeding,single exhaustive treadmill running was carried out for the O group.Exhaustive treadmill running was carried out for the R groups 6 days per week for total of two weeks.The samples were drawn from rats at 0 and 24 hours after exercise.The rats of O group were named O-0 h,O-24 h,respectively,the rats of R group were named R-0 h 、R-24 h,respectively.The mRNA and protein expression of IKr channel subunit in sinoatrial node were analyzed by real-time fluorescent quantitative PCR and Western Blot,the current density of IKr channel were analyzed by whole-cell patch clamp analysis.Results 1） ERG1b mRNA and protein expression of the repeated treadmill running R-0 h and R-24 h group were significantly lower than that of C and O-0 h group （P ＜0.01）.2）The current density of IKr of the repeated treadmill running R-0 h and R-24 h group were 0.89 ±0.03 pA/pF,1.02 ±0.07 pA/pF respectively,significantly lower than that of C and O-0 h group （P ＜ 0.01,P ＜ 0.01）.Conclusions Exhaustive exercise downregulates the sinoatrial node ERG1 b gene subunit expression,along with the corresponding current IKr,and may be one of the most important mechanism of exercise-induced sinoatrial node dysfunction and arrhythmia.

关 键 词：跑台训练 窦房结 快激活IKr通道 ERG1b亚基 

分 类 号：R87[医药卫生—运动医学]