柠檬苦素抑制PM2.5吸入诱导的大鼠气道炎性反应及黏液高分泌状态

Limonin inhibits the PM2.5 inhalation-induced airway inflammation and mucus hypersecretion in rats

目的探讨柠檬苦素在气道炎性反应及黏液高分泌形成过程中的作用。方法实验分为3组(n=10),即空白对照组、PM2.5组(雾化吸入PM2.5悬液复制大鼠慢性气道炎性反应模型)和PM2.5+柠檬苦素组(陈皮提取物干预),以ELISA、RT-PCR和Western blot检测各组大鼠肺部炎性反应因子、黏蛋白(MUC)及TAS2Rs mRNA和蛋白表达水平。结果 PM2.5组炎性反应因子IL-1β、CINC-1和黏蛋白MUC5AC、MUC5B的mRNA和蛋白合成表达水平较对照组明显增高(P<0.05),而支气管肺泡灌洗液(BALF)中MUC5AC分泌表达增加;PM2.5+柠檬苦素组TAS2R14的mRNA和蛋白表达水平进一步增高(P<0.05),而IL-1β、CINC-1和MUC5AC、MUC5B的转录和翻译表达水平较PM2.5组降低(P<0.05),BALF中的黏蛋白以MUC5B分泌表达增加为主。结论柠檬苦素吸入治疗可抑制黏蛋白的产生,促进黏蛋白的分泌,该效应是通过激活肺部TAS2Rs表达,使其对气道炎性反应的抗炎作用增强实现的。

Objective To investigate the inhibitory effect of limonin on airway inflammation and mucus hypersecretion.Methods The experiment was divided into three groups(n=10),namely blank control group,PM2.5 group(the rat models of chronic airway inflammation were established by aerosolized PM2.5 suspension)and PM2.5+limonin group(intervening with the extract from tangerine peel).mRNA,protein of inflammatory cytokines,mucin(MUC)and TAS2Rs were measured by ELISA,RT-PCR and Western blot respectively.Results The mRNA and protein expression of IL-1β,CINC-1 and MUC5AC and MUC5B in PM2.5 group were significantly higher than those in control group(P<0.05),and the expression of MUC5AC protein in broncho alveolar lavage fluid(BALF)was increased.Compared with PM2.5 stimulated group,mRNA and protein of TAS2R14 in PM2.5+limonin intervented group were significantly higher(P<0.05).Moreover,the expression of IL-1β,CINC-1 and MUC5AC,MUC5B was lower than PM2.5 group(P<0.05).While the expression of MUC5B was mainly increased in BALF.Conclusions The production of mucin can be inhibited by aerosolized limonin,meanwhile the secretion of mucin also can be promoted.This effect is achieved by activating the expression of TAS2Rs in the lungs,which enhances the anti-inflammatory effect of airway inflammation.