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目的探讨内毒素对培养小牛呼吸道上皮分泌内皮素－１（ＥＴ－１）、血栓烷素（ＴＸＡ２）、前列腺素Ｅ２（ＰＧＥ２）的影响，并探讨氧自由基的介导作用。方法大肠杆菌内毒素（ＬＰＳ）与培养小牛呼吸道上皮细胞孵育４小时后，测定培养呼吸道上皮细胞上清液中ＥＴ－１、ＴＸＡ２、ＰＧＥ２的含量。结果内毒素可明显促进小牛呼吸道上皮细胞ＥＴ－１、ＴＸＡ２的分泌，抑制ＰＧＥ２分泌，并呈浓度依赖性，用氧自由基清除剂ＳＯＤ、Ｃａｔ预处理呼吸道上皮细胞可拮抗内毒素的作用。结论内毒素诱发支气管高反应性形成，可能与其促进呼吸道上皮分泌ＥＴ－１、ＴＸＡ２，抑制ＰＧＥ２分泌有关，氧自由基可能参与其诱发支气管高反应性过程。
Objective To investigate the effects of endotoxin on the secretion of endothelin-1 (ET-1), thromboxanin (TXA2) and prostaglandin E2 (PGE2) in the respiratory tract of calf and to explore the effects of endotoxin on the mediation of oxygen free radicals. Methods The contents of ET-1, TXA2 and PGE2 in the supernatant of cultured airway epithelial cells were measured after incubation of E. coli endotoxin (LPS) and cultured calf respiratory epithelial cells for 4 hours. Results Endotoxin could significantly promote the secretion of ET-1, TXA2 and inhibit the secretion of PGE2 in the airway epithelial cells in a concentration-dependent manner. The pretreatment of respiratory epithelial cells with oxygen free radical scavengers SOD and Cat could antagonize the effects of endotoxin. Conclusion Endotoxin-induced bronchial hyperresponsiveness may be related to the promotion of ET-1 and TXA2 secretion and the inhibition of PGE2 secretion in the epithelium of the respiratory tract. Oxygen free radicals may be involved in the process of inducing bronchial hyperreactivity.