支气管上皮源性因子在吸烟及缺氧所致肺血管反应中的作用

Bronchial Epithelium-Derived Relaxing Factor Modulates Hypoxic Pulmonary Vasomotion During Hypoxia and Cigarette Smoking

用滴注、生物检测系统观察支气管上皮产物对肺血管张力的作用及缺氧与吸烟对支气管上皮产物生成的影响。发现离体猪支气管上皮可分泌舒张因子（EpDRF），使肺动脉舒张，其作用不依赖于内皮。缺氧的支气管灌流液使缺氧性肺血管收缩反应（HPV）由31.7％降至─7.4％，说明EPDRF在HPV中起调节作用。通烟使猪肺动脉张力降低23％，支气管通烟时灌流液使肺动脉张力降低47.5％，为通烟和EpDRF作用之和。

Using a superfusion apparatus the effect of epithehum-derived relaxing factor (EpDRF) released from pig bronchus on its pulmonary artery ring was studied druing normoxia,hypoxia and cigarette smoking.The results showed that,Krebs superfusate fluid ofbronchus significantly reduced the tension in endothelium intact and denuded pumonary artery by 21%,and 19%,respectively,which was preconstricted with phenylephrine.Hypoxia induced a constriction of endothelium intact pulmonary artery and augmented its ten sion by 31.7%, whereas the hypoxic Krebs superfusion fluid of bronchus caused a significant reduction in the tension of pulmonary artery by 7.4%. The tension of endothelium intact pulmonary artery was significantly attenuated by 47.5% when the superfusion fluid from bronchus had been exposed to cigarette smoking.Hypoxia after cigarette smoking only increased the tension in endothelium intact pulmonary artery by 11.8%. The results suggested that porcine bronchus could secrete an epithelium derived relaxing factor in normoxia,which relaxed the pulmonary smooth muscle directly.In hypoxia,the bronchus released EpDRF too.Cigarette smoking inhibited the hypoxic pulmonary vasoconstriction in pigs,it relaxed the pulnonary artery directly.Realease of EpDRF from bronchus could also be observed during cigarette smoking.The secretion of EpDRF in hypoxia and cigarette smoking may play a role in the modulation of hypoxic pulmonary vasoconstriction.