Zhao Limin, Zhang Xiaoyu, Kuang Hongyan, Wu Jizhen, Guo Yali, Ma Lijun
Department of Respiratory and Critical Care Medicine, Zhengzhou University People's Hospital, Zhengzhou, Henan, China.
Exp Lung Res. 2013 Sep;39(7):283-94. doi: 10.3109/01902148.2013.813610. Epub 2013 Aug 6.
Hyperplasia of airway smooth muscle cells (ASMC) is a major contributor to airway remodeling in asthma. Transient receptor potential vanilloid 1 (TRPV1) is an important channel to mediate Ca(2+) influx. This study explores the expression of TRPV1 channel and its effect on the proliferation and apoptosis in rat ASMC, in order to find a new target to treat airway remodeling in asthma.
Rats were sensitized and challenged with ovalbumin to replicate asthmatic models. Proliferating cell nuclear antigen (PCNA) was detected by immunohistochemistry. Reverse transcriptase-polymerase chain reaction, immunocytochemistry, and Western blot were used to detect the mRNA and protein expression of TRPV1 channel. Intracellular calcium ([Ca(2+)]i) was detected using confocal fluorescence Ca(2+) imaging. [(3)H] thymidine incorporation and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were used to observe the DNA synthesis and proliferation. TUNEL assay was used to detect the apoptosis of ASMC.
(1) The expression of PCNA was significantly increased in intact asthmatic rat ASMC. (2) The expression of TRPV1 channel was significantly increased in asthmatic rat ASMC. (3) [Ca(2+)]i in ASMC of the asthmatic group was significantly increased. After treatment with TRPV1 agonist capsaicin (CAP), [Ca(2+)]i was further increased, whereas [Ca(2+)]i was decreased after administration of TRPV1 antagonist capsazepine (CPZ) in ASMC of the asthmatic group. (4) The DNA synthesis and absorbance of MTT were significantly increased, while apoptosis was significantly decreased in asthmatic ASMC. CAP further enhanced proliferation and decreased apoptosis. CPZ significantly inhibited the effect of CAP in asthmatic ASMC.
TRPV1 channel was involved in the regulation of proliferation and apoptosis in asthmatic ASMC.
气道平滑肌细胞（ASMC）增生是哮喘气道重塑的主要促成因素。瞬时受体电位香草酸受体1（TRPV1）是介导Ca(2+)内流的重要通道。本研究探讨TRPV1通道在大鼠ASMC中的表达及其对细胞增殖和凋亡的影响，以期找到治疗哮喘气道重塑的新靶点。
用卵清蛋白致敏并激发大鼠以复制哮喘模型。采用免疫组织化学法检测增殖细胞核抗原（PCNA）。运用逆转录聚合酶链反应、免疫细胞化学和蛋白质免疫印迹法检测TRPV1通道的mRNA和蛋白表达。采用共聚焦荧光Ca(2+)成像检测细胞内钙（[Ca(2+)]i）。运用[3H]胸腺嘧啶核苷掺入法和3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（MTT）法观察DNA合成及细胞增殖情况。采用TUNEL法检测ASMC的凋亡情况。
（1）在完整的哮喘大鼠ASMC中，PCNA表达显著增加。（2）哮喘大鼠ASMC中TRPV1通道表达显著增加。（3）哮喘组ASMC中的[Ca(2+)]i显著升高。用TRPV1激动剂辣椒素（CAP）处理后，[Ca(2+)]i进一步升高，而给予TRPV1拮抗剂辣椒平（CPZ）后，哮喘组ASMC中的[Ca(2+)]i降低。（4）哮喘ASMC中DNA合成及MTT吸光度显著增加，而凋亡显著减少。CAP进一步增强增殖并减少凋亡。CPZ显著抑制CAP对哮喘ASMC的作用。
TRPV1通道参与哮喘ASMC增殖和凋亡的调控。
