模拟大气混合污染物对大鼠肺表面蛋白A影响

目的筛选敏感的生物标志物,探讨大气混合污染物对肺泡II型上皮细胞(AT-II)的损伤及其机制,为控制大气污染的危害提供理论依据。方法使用便携式PM2.5采样器和47mm玻璃纤维滤膜采集大气粉尘样品,制成生理盐水混悬液,实验大鼠气管注入混悬液及动态吸入SO2、NO2、CO混合气,制备大气混合污染物吸入动物模型,测定染毒不同时间血清及支气管肺泡灌洗液(BALF)中肺表面活性蛋白(SP-A)水平,肺组织中SP-A的mRNA及蛋白表达。结果染毒7 d组大鼠肺组织中SP-A mRNA表达为1.816±1.299,明显高于染毒1、30 d组(0.930±0.587;0.902±0.378)及对照组;染毒30 d组大鼠肺组织中SP-A表达吸光度值为0.385±0.068,明显低于染毒7 d组(0.438±0.069)及对照组;染毒30 d组大鼠BALF中SP-A水平为47.09±5.78,明显低于染毒1、7 d组(54.72±6.15;58.82±9.76)及对照组;染毒30 d组大鼠血清中SP-A水平明显高于染毒1、7 d组及对照组。结论 SP-A是反映AT-II功能受损严重程度的肺特异性指标。

Effects of air pollutants on SP-A mRNA expression in pulmonary tissue of rats

Objective To screen sensitive biologic markers and to explore the mechanism of the damage in pulmonary alveolus type II epithelial cell(AT-II) exposed to atmospheric mix pollutants.Methods The air particulate samples were collected with portable sampler for particulate matter of 2.5 μm in diameter and glass fiber filter(47 mm).The particulates collected were mixed with normal saline and gavaged into trachea of the rats inhaling mixed air of sulfur dioxide,nitrogen dioxide,and carbon monoxide.The effects of air pollutants on pulmonary surfactant-associated protein A(SP-A) expression in pulmonary tissue,blood,bronchoveloar lavage fluid(BALF) of the rats were determined.Results The SP-A mRNA expression level in pulmonary tissue 7 days after the exposure(1.86±1.299) was significantly decreased compared to that of rats with 1 or 30 days exposure(0.930±0.587,0.902±0.378) and that of the control group.The SP-A expression level in pulmonary tissue in 30 days exposure group was significantly decreased compared to 7 days exposure and the control group.The SP-A expression level in BALF of the rats with 30 days exposure was significantly decreased compared to that of with 1 or 7 days exposure and the control group.The SP-A expression level in blood in 30 days exposure group was significantly decreased compared to 1 day,7days exposure and the control group.Conclusion SP-A reflects the function of lung alveolus type II cells and SP-A could be used as a specific indicator of lung function.