Shi Zhihui, Chen Yan, Pei Yanfang, Long Yingjiao, Liu Caihong, Cao Jun, Chen Ping
Division of Respiratory Disease, Department of Internal Medicine, The Second Xiangya Hospital, Central-South University, Changsha 410011, China.
J Thorac Dis. 2017 Jan;9(1):30-41. doi: 10.21037/jtd.2017.01.23.
Apoptosis has been demonstrated to be an important upstream event in the pathogenesis of chronic obstructive pulmonary disease (COPD). Cyclooxygenase-2 (COX-2) seems to be biologically relevant in COPD. However, the role of COX-2 in the apoptosis in vascular endothelial cells induced by cigarette smoke extract (CSE) remains to be elucidated. Our recent study found that the prostacyclin, one of the COX products in the microvascular endothelium, inhibited apoptosis in the emphysematous lungs of rats induced by CSE. In order to clarify the role of COX-2 in the apoptosis of vascular endothelial cells induced by CSE, we performed the present experiment to elucidate it.
Twenty surgical lung specimens were obtained from 6 patients with COPD, 7 smoking controls and seven nonsmoking controls. The apoptotic index (AI) and COX-2 protein expression were detected in lung tissues. To further investigate the effects of CSE on the apoptosis and COX-2 expression in a human vascular endothelial cell line, the apoptosis rate and COX-2 expression were examined in human umbilical vein endothelial cells (ECV304) under exposure to varied concentrations of CSE as well as under exposure to 5.0% CSE for varied durations. Repeatedly, the apoptosis rate and COX-2 expression in ECV304 cells under 5.0% CSE were examined after exposing to varied concentrations of celecoxib, a highly selective COX-2 inhibitor.
Significantly increased AI and expression of COX-2 were found both in the lungs of patients with COPD and smoking controls compared with nonsmoking controls. The CSE induced apoptosis in ECV304 cells in means of both dose-dependent and time-dependent manners. The COX-2 was slightly expressed in the cells after exposing to 5% CSE for 3 and 6 h, and markedly expressed after the exposure time for 9 and 12 h, but vanished after 24 h of the exposure. Of interest, with the completely block of the COX-2 expression by celecoxib at 50.0 µmol/L, the apoptosis rate was markedly increased again in ECV304 cells under exposure to 5.0% CSE.
Endothelial cell apoptosis and the expression of COX-2 protein were increased in both COPD patients and CSE-induced vascular endothelial cells. Of interest, it seems that the COX-2 probably had a protective role against the apoptosis in the vascular endothelial cells induced by cigarette smoking.
细胞凋亡已被证明是慢性阻塞性肺疾病（COPD）发病机制中的一个重要上游事件。环氧化酶-2（COX-2）在COPD中似乎具有生物学相关性。然而，COX-2在香烟烟雾提取物（CSE）诱导的血管内皮细胞凋亡中的作用仍有待阐明。我们最近的研究发现，前列环素是微血管内皮中COX的产物之一，可抑制CSE诱导的大鼠肺气肿肺组织中的细胞凋亡。为了阐明COX-2在CSE诱导的血管内皮细胞凋亡中的作用，我们进行了本实验以进行研究。
从6例COPD患者、7例吸烟对照者和7例非吸烟对照者中获取20份手术肺组织标本。检测肺组织中的凋亡指数（AI）和COX-2蛋白表达。为了进一步研究CSE对人血管内皮细胞系细胞凋亡和COX-2表达的影响，检测了人脐静脉内皮细胞（ECV304）在不同浓度CSE作用下以及在5.0% CSE作用不同时间后的凋亡率和COX-2表达。同样，在ECV304细胞暴露于5.0% CSE后，检测在不同浓度的塞来昔布（一种高度选择性COX-2抑制剂）作用下细胞的凋亡率和COX-2表达。
与非吸烟对照者相比，COPD患者和吸烟对照者肺组织中的AI和COX-2表达均显著增加。CSE以剂量依赖性和时间依赖性方式诱导ECV304细胞凋亡。在暴露于5% CSE 3小时和6小时后，COX-2在细胞中轻度表达，在暴露9小时和12小时后明显表达，但在暴露24小时后消失。有趣的是，当塞来昔布在50.0 μmol/L时完全阻断COX-2表达后，暴露于5.0% CSE的ECV304细胞凋亡率再次显著增加。
COPD患者和CSE诱导的血管内皮细胞中内皮细胞凋亡和COX-2蛋白表达均增加。有趣的是，COX-2似乎对吸烟诱导的血管内皮细胞凋亡具有保护作用。
