β1肾上腺素能受体自身抗体对大鼠心肌细胞微区力及细胞内钙离子变化的影响

Effects of β1 adrenergic receptor autoantibodies on the micro-mechanics of a rat myocardial cell and the concentration of intracellular calcium

目的：测定β1肾上腺素能受体（β1-AR）自身抗体对单个心室肌细胞微区力和细胞内钙离子浓度变化的影响，在细胞和分子水平上探讨β1-AR自身抗体导致心脏疾病的机制。方法利用原子力显微镜（ AFM）和激光扫描共聚焦显微镜（ LSCM）组合成的联合成像系统对结合β1-AR自身抗体前后的急性分离单个大鼠心室肌细胞微区力进行测定，同时观察心室肌细胞收缩频率以及细胞内钙离子浓度的变化。结果（1）β1-AR自身抗体与单个心室肌细胞结合后细胞微区力和细胞收缩频率均增大。结合前原子力F＝（44～51） nN，收缩频率为（0.17±0.04） Hz；结合后原子力F＝（76～82） nN，收缩频率为（0.40±0.03） Hz；结合前后心室肌细胞收缩频率差异有统计学意义（P＜0.05）。（2）结合抗体后与结合抗体前相比，细胞收缩时钙离子荧光相对吸光度值增加的幅度明显升高（154.3％±16.7％vs 102.1％±12.3％，P＜0.01）。结论β1-AR自身抗体引起心室肌细胞收缩频率、细胞微区力、细胞内钙离子浓度的改变。

Objective To evaluate the effects of β1 adrenergic receptor （β1-AR） autoantibodies on the micro-mechanics of a single rat ventricular myocyte and the concentration of intracellular calcium for investigating the pathogenic mechanism of heart disease caused by β1-AR autoantibody on both cellular and molecular levels .Methods The micro-mechanics of an acutely isolated single myocardial cell from rat was detected by using the atomic force microscopy （ AFM） in combination with laser scanning confocal micro-scope （LSCM） before and after binding to β1-AR autoantibodies.The ventricular myocyte contraction and the intracellular calcium concentration were observed as well .Results The micro-mechanics of a single ventricular myocyte was increased from （44-51） nN to （76-82） nN after binding to β1-AR autoantibodies. Its contraction frequency was also increased from （0.17±0.04） Hz to （0.40±0.03） Hz （P〈0.05）.More-over, the intracellular calcium fluorescence intensity was increased significantly during contraction in com -parison with that before binding to β1-AR autoantibodies [ （ 102.1 ±12.3 ） % vs （ 154.3 ±16.7 ） %, P〈0.01 ] .Conclusion β1-AR autoantibody could affect the contraction and the micro-mechanics of ventricu-lar myocytes and the intracellular calcium concentration in ventricular myocytes .