摘要
机动车尾气是我国大气细颗粒物PM2.5污染的主要来源之一,长期暴露于机动车尾气对动物呼吸系统及其他多种脏器造成损害。为探索长期暴露于汽油燃烧的汽车尾气对小鼠肺组织的损伤作用,将51只雄性8周龄SPF级ICR小鼠随机分为7个处理。其中,空气对照组1个(6只);箱体对照组3个:0.5h对照组(5只)、1h对照组(8只)、2h对照组(8只);汽油车尾气暴露组3个:0.5h暴露组(8只)、1h暴露组(8只)、2h暴露组(8只)。小鼠每天在自制染毒箱中暴露0.5h、1h、2h。95d的暴露实验后,处死实验鼠,测定其肺组织的炎症因子白介素-6(IL-6)、乳酸脱氢酶(LDH)、肿瘤坏死因子-α(TNF-α)、转化生长因子β(TGF-β),并制作小鼠肺部病理学切片进行HE染色。暴露实验过程中,观察记录小鼠行为特征,测定箱体内O2、NOx、NO2、NO、SO2和CO的浓度。采集汽油车尾气的PM2.5,对其水溶性阴离子(F^-、Cl^-、NO2^-、NO3^-、SO4^2-)、水溶性阳离子(Na^+、NH4^+、Ca^2+、K^+、Mg^2+)、有机碳(OC)和元素碳(EC)、7种重金属元素(Cu、Ni、Mn、Zn、Pb、As、Cr)、16种多环芳烃(PAHs)浓度等进行了测定。结果表明:(1)亚慢性染毒箱内汽油车尾气PM2.5所分析的化学物质中,OC浓度最高,占PM2.5中总化学物质浓度的75.5%;其次是EC,占22.9%;再次是阴离子和阳离子,分别占1.11%和0.27%。(2)3个暴露组小鼠活跃程度降低,暴露5~8min后进入睡眠或休息状态,呼吸频率降低,小鼠通过这些行为来减少汽油车尾气的伤害。(3)汽油车尾气长期暴露组的体重增长率与各自对照组之间不存在显著差异,但2h暴露组体重增长率明显小于2h对照组,且2h暴露组在第14周开始体重有下降的趋势。(4)与对照组相比,1h暴露组的IL-6和0.5h暴露组的TNF-α显著升高,说明汽油车尾气暴露造成小鼠肺炎症损伤,使IL-6、TNF-α的分泌增加。随着暴露时间的延长,IL-6和TNF-α表现为2h暴露组分别显著低于1h暴露组和0.5h暴露组,意味长期暴露后小鼠肺部受到严重伤害,免疫力严重下降,不再有积极的抗炎性反应。(5)组织病理观察表明,与开放对照组比较,3个汽油车尾气暴露组小鼠肺部组织充血较为严重,大量淋巴细胞、中性粒细胞浸润,肺泡间质增生明显,呈现出随时间延长损伤加重的梯度差异。(6)汽油车尾气长期暴露可致实验鼠肺脏损伤,且随着暴露时间的增加,对肺组织造成的损伤程度增加。
Motor vehicle exhaust is one of the main sources of PM 2.5 pollution in China. Long-term exposure to vehicle exhaust causes damage to animal respiratory system and other organs. To explore the effects of long-term exposure to gasoline-burning vehicle exhaust on lung tissue damage in mice, 51 male 8-week-old SPF-class ICR mice were randomly divided into 7 groups. Among them, one air control group (6 mice);three control groups: 0.5 h control group (5 mice), 1 h control group (8 mice), and 2 h control group (8 mice);three gasoline exhaust exposure groups: 0.5 h exposure group (8 mice), 1 h exposure group (8 mice), and 2 h exposure group (8 mice). Mice were exposed to gasoline engine exhaust in homemade chambers for 0.5 h, 1 h, and 2 h daily. After 95 days of exposure, the mice were sacrificed and their lung tissues were measured for inflammatory factors interleukin-6 (IL-6), lactate dehydrogenase (LDH), tumor necrosis factor-α(TNF-α), and transform growth factor β(TGF-β), and pulmonary pathology sections were made for HE staining. During the exposure experiment, the behavioural characteristics of the mice were observed and the concentrations of O2 , NOx , NO2 , NO, SO2 and CO in the exposure chamber were determined. In addition, PM 2.5 gasoline vehicle exhaust particles were collected and analysed for concentrations of water-soluble anions (F^-, Cl^-, NO2^-, NO3^-, SO4^2-), water-soluble cations (Na^+, NH4^+, Ca^2+, K^+, Mg^2+), organic carbon (OC) and elementary carbon (EC), seven heavy metals (Cu, Ni, Mn, Zn, Pb, As, Cr) and 16 polycyclic aromatic hydrocarbons (PAHs). The results showed that:(1) Among the chemical species analyzed in the subchronic exposure chamber, the OC concentration was the highest, accounting for 75.5% of the total chemical concentration in PM 2.5;followed by EC, accounting for 22.9%;and then anion and cation, accounting for 1.11% and 0.27%, respectively.(2) The mice in the three exposed groups were less active. After 5-8 minutes of exposure, they entered sleep or rest, with the respiratory rate decreased, and these behaviours can reduce the damage from gasoline exhaust emissions.(3) There was no significant difference for weight growth rate between the parallel exposure and control groups, but the growth rate of the 2 h exposure group was significantly lower than that of the 2 h control group, and the 2 h exposure group has a weight decline tendency at the 14 th week.(4) Compared with the control group, TNF-α in the 0.5 h exposure group and IL-6 in the 1 h exposure group were significantly increased, indicating that exposure to gasoline exhaust gases induced mouse lung inflammation injury, with increased secretion of IL-6 and TNF-α. With the prolongation of exposure time, IL-6 and TNF-α were significantly lower in the 2 h exposure group than that in the 1 h exposure group and 0.5 h exposure group respectively, which indicates that the lungs of the mice were seriously injured and the immunity was seriously reduced, with no positive anti-inflammatory response.(5) Histopathological observation showed that pulmonary congestion was more serious in the three exposure groups than in the control groups, a large number of lymphocytes and neutrophils infiltrated, and the alveolar interstitial hyperplasia was obvious, showing a gradient difference of damage aggravation with time.(6) Long-term exposure of gasoline vehicle exhaust can cause lung injury in mice, and the degree of damage to lung tissue increases with increasing exposure time.
作者
程志斌
杨峥
刘艳菊
郭青云
朱明淏
钟震宇
李俊芳
单云芳
张鹏骞
刘田
Cheng Zhibin;Yang Zheng;Liu Yanju;Guo Qingyun;Zhu Minghao;Zhong Zhenyu;Li Junfang;Shan Yunfang;Zhang Pengqian;Liu Tian(Beijing Milu Ecological Research Center,Beijing 100076,China)
出处
《生态毒理学报》
CAS
CSCD
北大核心
2019年第2期298-310,共13页
Asian Journal of Ecotoxicology
基金
国家自然科学基金(41475133)
关键词
汽油车尾气
颗粒物
小鼠
化学成分
染毒箱
炎症因子
病理伤害
gasoline engine exhaust
PM2.5
mice
chemical composition
exposure chamber
inflammatory factor
pathological injury
