抗M2受体自身抗体对家兔心房离子通道的影响

Effects of anti-M2 receptor autoantibody on rabbit atrial ion channels

目的探讨抗M2受体自身抗体对家兔心房离子通道的影响。方法新西兰大白兔30只,随机分为实验组和对照组,每组各15只。实验组通过静脉注射合成多肽制备抗M2受体自身抗体阳性家兔模型,对照组皮下注射生理盐水。7次免疫后处死动物,留取心房组织标本。RT-PCR检测乙酰胆碱敏感钾通道m RNA表达,Western blot检测M2受体、乙酰胆碱敏感钾通道和L型钙通道的蛋白表达。两组间比较采用t检验。结果与对照组相比,实验组的乙酰胆碱敏感钾通道GIRK1亚基m RNA表达上调(左:1.86±0.19 vs.0.91±0.17,P<0.05;右:1.31±0.25 vs.0.33±0.15,P<0.05),GIRK4亚基m RNA亦升高(左:1.52±0.24 vs.0.42±0.13,P<0.05;右:1.12±0.18 vs.0.21±0.11,P<0.05)。与对照组相比,实验组M2受体(左:2.81±0.27 vs.1.41±0.14,P<0.05;右:1.86±0.22 vs.0.59±0.07,P<0.05)、乙酰胆碱敏感钾通道蛋白(左:2.74±0.35 vs.1.47±0.24,P<0.05;右:2.15±0.41 vs.0.63±0.1,P<0.05)表达均增加,L型钙通道的蛋白水平降低(左:0.89±0.12 vs.1.55±0.17,P<0.05;右:0.92±0.14 vs.1.72±0.16,P<0.05)。结论抗M2受体自身抗体能上调离子通道表达,为心房颤动的发生提供基质。

ObjectiveTo investigate the effects of anti-M2 receptor autoantibody （M2-AAB） on rabbit atrial ion channels.MethodsThirty New Zealand white rabbits were randomly divided in two groups, M2 group and control group. Each group contains fifteen rabbits. M2 group was immunized with synthetic peptide corresponding to M2 acetylcholine receptor and control group was injected with saline. The mRNA level of acetylcholine sensitive potassium channel were detected using RT-PCR. The protein expression of M2-receptor, acetylcholine sensitive potassium channel and L-type calcium channel were detected using Western blot.t-test was used to compare means between two groups.ResultsThe mRNA level of GIRK1 in both left and right atrium were up-regulated in M2-AAB positive rabbits compared with control rabbits （left： 1.86±0.19vs. 0.91±0.17,P〈0.05; right： 1.31±0.25vs. 0.33±0.15,P〈0.05）. The mRNA level of GIRK4 in both left and right atrium were up-regulated in M2 group compared with control group （left： 1.52±0.24vs. 0.42±0.13,P〈0.05; right： 1.12±0.18vs. 0.21±0.11,P〈0.05）. Compared with control group, the protein levels of M2 receptor in both left and right atrium were up-regulated in M2 group （left： 2.81±0.27vs. 1.41±0.14,P〈0.05; right： 1.86±0.22vs. 0.59±0.07,P〈0.05）. The protein levels of GIRK4 in both left and right atrium were up-regulated in M2-AAB positive rabbits compared with control rabbits （left： 2.74±0.35vs. 1.47±0.24,P〈0.05; right： 2.15±0.41vs. 0.63±0.1,P〈0.05）. The protein levels of L-type calcium channel are down-regulated in M2 group compared with control group （left： 0.89±0.12vs.1.55±0.17,P〈0.05; right： 0.92±0.14vs. 1.72±0.16,P〈0.05）.ConclusionAnti-M2 receptor autoantibody can convert the ion channels expression profile of atrial, which make patients more vulnerable to atrial fibrillation.