PM2.5组分对大鼠支气管收缩及炎症因子表达的影响

Effects of different components of PM2.5 on contractile responses and inflammatory mediators in rat bronchi

目的研究PM2.5组分对大鼠支气管收缩性受体介导的收缩反应的影响,评价PM2.5组分对支气管炎症因子表达的影响。方法采用体外器官培养模型,将1.0μg/ml PM2.5的水溶性和脂溶性组分与大鼠支气管环培养24 h,使用肌张力描记仪检测毒蕈碱受体、5-羟色胺(5-HT)受体和内皮素(ET)受体介导的收缩反应。使用实时荧光定量PCR技术检测支气管中炎性因子[肿瘤坏死因子-α(TNF-α)、白介素-6(IL-6)、基质金属蛋白酶9(MMP9)、白介素-1β(IL-1β)、一氧化氮合酶2(NOS2)]mRNA的表达。结果1.0μg/ml PM2.5脂溶性组分能明显增加大鼠支气管毒蕈碱受体介导的收缩反应,支气管收缩量效曲线Emax为(250.4±21.1)%,明显高于溶剂培养组[DMSO培养组,Emax=(147.2±27.4)%],差异有统计学意义(P<0.05)。1.0μg/ml PM2.5脂溶性组分可明显增加内皮素受体介导的收缩反应,ETB受体激动剂S6c所引起收缩量效曲线的Emax为(221.8±10.4)%,明显高于溶剂培养组[Emax=(167.3±12.4)%],差异有统计学意义(P<0.05);ETA受体激动剂ET-1所引起收缩量效曲线的Emax为(153.9±12.6)%,明显高于溶剂培养组[Emax=(110.4±18.7)%],差异有统计学意义(P<0.05)。与溶剂培养组相比,PM2.5组分对5-HT诱导的支气管收缩反应无明显增强作用(P>0.05)。RT-PCR结果显示,与溶剂培养组相比,1.0μg/ml PM2.5脂溶性组分培养24 h后,大鼠支气管炎性因子TNF-α、MMP9和IL-1β的mRNA表达明显升高,差异有统计学意义(P<0.05);对NOS2和IL-6的mRNA表达无明显影响(P>0.05)。结论PM2.5脂溶性组分能增加大鼠支气管毒蕈碱受体和内皮素受体介导的收缩反应,能增加炎性因子TNF-α、MMP9和IL-1βmRNA的表达,而同浓度的PM2.5的水溶性组分无明显作用。提示PM2.5脂溶性组分在支气管收缩功能和炎性反应中有重要作用。

Objective To study the effects of different components of PM2.5 on the contractile response mediated by contractile receptor and the expression of inflammatory mediators in rat bronchi.Methods Isolated bronchi segments were cocultured with 1.0μg/ml water-soluble PM2.5 or DMSO-soluble components of PM2.5 for 24 h in vitro.Wire myograph was carried out to record contractile responses of bronchi mediated with muscarinic(M),5-HT,ETB and ETA receptors.Quantitative real-time PCR was used to estimate the mRNA expression of inflammatory mediators,such as TNF-α,IL-6,MMP9,IL-1β,NOS2.Results Compared with DMSO groups,1.0 mg/ml of DMSO-soluble PM2.5 significantly increased the M receptor-mediated contractile response curves in rat bronchi[DMSO:Emax=(147.2±27.4)%;PM2.5:Emax=(250.4±21.1)%;P<0.05],as well as endothelin receptor-mediated contraction response,the Emaxof S6 c-induced contractile response curves was significantly enhanced from(167.3±12.4)%to(221.8±10.4)%(P<0.05),the Emaxof ET-1-induced contractile response curves was significantly enhanced from(110.4±18.7)%to(153.9±12.6)%(P<0.05).While,1.0μg/ml water-soluble PM2.5 or DMSOsoluble PM2.5 did not effect the 5-HT-induced contractile curve compared with the solvent groups.1.0 mg/ml of DMSO-soluble PM2.5 cultured for 24 h increased the mRNA expression levels of TNF-α,MMP9 and IL-1β(P<0.05),and did not affect NOS2 and IL-6 mRNA expression.Conclusion 1.0μg/ml DMSO-soluble PM2.5 may increase the contractile response mediated by M,ETB and ETA receptors on rat bronchi,and increase the expression of TNF-α,MMP9 and IL-1βmRNA.While water-soluble PM2.5 can not increase bronchial contractile response mediated by contractile receptors.DMSO-soluble PM2.5 can play an important role in bronchial constriction function and inflammatory response.