LTD4诱导大鼠气道平滑肌细胞收缩的机制

Contraction of Airway Smooth Muscle Cells Induced by LTD4

目的探讨LTD4对气道平滑肌细胞（ASMC）收缩的机制。方法 以Fluo-3/AM作为细胞内游离Ca2+示踪剂,通过激光共聚焦显微镜观察LTD4对原代大鼠ASMC细胞内钙离子浓度（[Ca2+]i）及细胞收缩的影响;观察胞外Ca2+、G蛋白。蛋白激酶C（PKC）、丝裂素活化蛋白（MAPK）在LTD4生理效应中的作用。结果 LTD4刺激后,[Ca2+]i上升前有一个潜伏期,随后缓慢增加。随着LTD4浓度上升,潜伏期逐渐缩短（P<0.05）。在无钙溶液中,LTDA诱导的[Ca2+]i上升明显抑制（P<0.01）。随LTD4浓度上升,ASMC收缩程度也有增强趋势（P>0.05）。LTD4诱导的[Ca2+]i上升与细胞收缩程度显著相关（P<0.01）。PTX对LTD4诱导ASMC[Ca2+]i上升和收缩均有明显抑制作用。Staurosporine对[Ca2+]i上升无明显影响,但对收缩有明显抑制作用。PD098059对[Ca2+]i上升元明显影响,对收缩有部分抑制。结论 在大鼠ASMC中,LTD4诱导[Ca2+]i缓慢上升,并有潜伏期。[Ca2+]i在LTD4诱导ASMC收缩中起关键作用。G蛋白、PKC、MAPK在LTD4生理效应中起重要作用。

To investigate the mechanism of contraction of airway smooth muscle cells (ASMC) induced by LTD4. Methods With Fluo - 3/AM as the indicator of intracellular free Ca2+ , the primary rat culture of ASMC was investigated by the laser scan confocal microscope to observe the effect of LTD4 on [Ca2+]i and contraction, and the role of extracellular Ca2+,G protein,PKC, and MAPK in contraction induced by LTD4. Results [Ca2+]i induced by LTD4 rose slowly and had a latent period. Duration of the latent period correlated with LTD4 concentrations ( P <0. 05). The Ca2+- free medium had an inhibitory effect on [Ca2+]i rise( P <0. 01). Maximal contraction had an increase tendency with LTD4 concentration increase ( P > 0.05). There was positive correlation between the contraction and but [Ca2+]i rise( P <0. 01). PTX significantly inhibited both [Ca2+]i rise and contraction. Staurosporine had no effect on [Ca2+]i rise, but inhibited contraction. PD098059 also had no effect on [Ca2+]i rise and partly inhibited contraction. Conclusion In rat ASMC, [Ca2+]i induced by LTD4 rose slowly and had a latent period, it plays a vital role in ASMC contraction induced by LTD4. G protein, PKC and MAPK may also play important roles in the physiological effect of LTD4.