瞬时感受器电位香草酸受体1在低氧诱导肺动脉平滑肌细胞内钙升高中的作用

目的观察记录低氧条件培养的人肺动脉平滑肌细胞中瞬时感受器电位香草酸受体1(transient potential vanilloid receptor1,TRPV1)对细胞内Ca2+浓度(用340nm/380nm的荧光强度比值表示)的影响,探讨TRPV1在低氧性肺动脉平滑肌细胞增生中的作用。方法应用4′,6-二脒基-2-苯基吲哚(4′,6-diamidino-2-phenylindole,DAPI)染色、流式细胞周期测定以及细胞内Ca2+浓度测定的方法检测细胞增生及细胞内Ca2+浓度变化。结果低氧能明显促进人肺动脉平滑肌细胞的增生,升高人肺动脉平滑肌细胞内静息Ca2+浓度,显著加强环并偶氮酸(cyclopiazonic acid,CPA)诱发的库容性Ca2+内流(capacitative Ca2+entry,CCE),上述效应均可被TRPV1阻断剂Capsazepine(CPZ)所抑制。结论在人肺动脉平滑肌细胞中,TRPV1可能是低氧所致细胞内Ca2+浓度增加、CCE增强和细胞过度增生的重要途径或调制因素。

Role of Transient Potential Vanilloid Receptor 1 Channels in Hypoxia-induced Cytosolic Ca2+ Increase of Human Pulmonary Arterial Smooth Muscle Cells

Objective To investigate the role of transient potential vanilloid receptor 1(TRPV1) channels on cytosolic Ca²⁺ concentration(340 nm/380 nm ratio of the fluorescence image) of hypoxic human pulmonary artery smooth muscle cells(HPASMCs) and its possible signal pathway. Methods 4',6-diamidino-2-phenylindole(DAPI) staining and flow cytometry were used to detect the proliferation of HPASMCs under normoxia or hypoxia (3％O₂, 72 h) conditions. Cytosolic Ca²⁺ concentration(［Ca²⁺］cyt) was measured with a dynamic digital imaging system. Results The capability of HPASMCs proliferation significantly increased under hypoxic condition. Capsazepine(a TRPV1 channel inhibitor) could inhibit the HPASMCs proliferation. Hypoxia markedly increased resting cytosolic Ca²⁺ concentration and enhanced cyclopiazonic acid-induced capacitative Ca²⁺ entry(CCE) in HPASMCs. Capsazepine(10 μM) decreased CCE under hypoxia condition, but there was no effect on normoxia cultured group. Conclusion These results suggest that TRPV1 may be a critical pathway or mediator in hypoxia-induced increase of cytosolic Ca²⁺ concentration, CCE and the proliferation of HPASMCs.