腺苷酸环化酶介导电针预治疗对离体缺血心肌细胞的保护作用

Protective Effect of Adenylate Cyclase Mediated Pretreatment of Electric Needle on Ischemic Cardiac Muscular Cells in vitro

目的:观察电针预治疗对模拟全心缺血心肌细胞的保护作用,并探讨β-AR信号转导站点中腺苷酸环化酶(adenylyl cyclase,AC)介导上述针刺保护效应中的作用。方法:采用离体心脏模拟全心缺血(低灌流)模型,观察正常对照(NC)组、缺血再灌注(IR)组和缺血再灌注+电针(EA)组心肌细胞存活率,心肌细胞内静息钙水平([Ca2+]i)以及各组心肌细胞在Forskolin作用下钙瞬变的变化。结果:EA组心肌细胞存活率明显高于IR组(P<0.01),其心肌[Ca2+]i明显低于IR组(P<0.01),且EA组缺血心肌细胞在Forskolin作用下钙瞬变增加的波幅与相应的IR组比较明显降低(P<0.01)。结论:电针预治疗可以有效地提高缺血心肌细胞的存活率,改善缺血心肌细胞内钙超载情况,抑制缺血引起的AC活性过度增加。

Objective： To observe the protective effect of electroacupuncture （EA） pretreatment on ventricutar myocytes isolated from perfused hearts subjected to simulative global myocardial ischemia and reperfusion and to explore if adenylyl cyclase （AC） is involved in the mediation of the cardioprotection produced by EA. Methods：All the hearts were isolated from SD rats which were pretreated previously with EA for 30 min once a day in 3 consecutive days and perfused with landrendorff perfusion system and subjected to a 30-min global ischemia followed by a 10-min reperfusion. The percentage of the living （rod-shape） myocytes over dead myocytes and the resting intracellular calcium （[Ca2＋ ]i ） concentration in single cardiac myocyte were measured and compared among the NC, IR and EA groups. The change in amplitude of electricallyinduced [Ca2＋ ]i transient caused by Forskolin was also measured in the aforementioned groups respectively. Results：The percentage of living cells in EA group was significantly higher than IR group （ P 〈 0.01 ） and the concentration of resting [ Ca2＋] i in EA group was significantly lower than IR group （ P 〈 0.01 ）. Interestingly, after the animals were pretreated with EA, the forskolin-induced enhancement of the amplitude [ Ca2＋ ]i transient was only 78.41% in EA group, much lower than that in IR group （P 〈 0.01 ）. Conclusion： EA pretreatment can protect the ventricular myocytes from injury induced by simulative global ischemia and reperfusion, which was mediated by the inhibition of AC responsiveness.