大黄酸抑制气道平滑肌收缩机制研究

Mechanism Research of Contraction Inhibition of Airway Smooth Muscle with Rhein

目的研究大黄酸是否抑制气道平滑肌收缩及其机制。方法取SPF级BALB/c♂小鼠气管环,将气管环置于恒温灌流系统中,通过JH-2型张力换能器记录气管环张力值。使用80 mmol/L钾(K+)收缩气管环,待气管环张力达到稳定后,分别加入终浓度为1. 00、3. 16、10.00、31. 60、100.00、177. 80、200. 00μmol/L的大黄酸,加入等量的溶剂作为对照。用膜片钳记录L-型电压依赖性钙通道(L-type voltage-dependent calcium channel,LVDCC)电流,大黄酸可以抑制LVDCC电流。用TILL钙成像系统测量平滑肌细胞内钙浓度变化。结果当加入177. 80μmol/L大黄酸时,气管环舒张比率达到最大,为(92. 7±8. 0)%,抑制LVDCC介导的电流、LVDCC介导的钙内流,以及钙内流引起的收缩。结论大黄酸可通过抑制LVDCC抑制气道平滑肌收缩。

Objective To investigate the relaxant effect of rhein on mouse airway smooth muscle and the underlying mechanism.Methods SPF BALB/c male mice were sacrificed to isolate the tracheal rings(TRs).After balancing in the perfusion system,the contraction tension of the TRs was recorded with JH-2 tension recording system.The TRs were precontracted using 80 mmol/L K+.When the muscle tension of the TRs reached a steady state,the rhein was accumulatively added at concentrations of 1.00,3.16,10.00,31.60,100.00,177.80,200.00μmol/L,respectively,and the tension changes were observed.The control experiments were also performed.The effects of rhein on the currents of the L-type voltage-dependent Ca2+channels(LVDCC)were recorded using patchclamp technique.Similarly,the effects of rhein at different concentrations on the levels of intracellular Ca2+([Ca2+]i)in airway smooth muscle cells were recorded using TILL calcium imaging system.Results The relaxant effects induced by rhein of 177.80μmol/L reached the maximal value(92.7±8.0)%.Rhein inhibited LVDCC-mediated currents and LVDCC-mediated increases of[Ca2+]i,as well as contraction caused by calcium influx.Conclusion Rhein inhibits contraction of airway smooth muscle via inhibiting LVDCC.