北京不同污染天气PM_(2.5)和PM_(10)染毒对大鼠生理病理参数的影响

Influence of PM_(2.5) and PM_(10) Exposure on Physiological and Pathological Parameters of Rats under Different Polluted Weather in Beijing

为探讨北京不同污染天气大气可吸入颗粒物PM_(10)和细颗粒物PM_(2.5)污染对雄性大鼠血常规、氧化损伤、炎症反应和肺组织的影响,将64只雄性8周龄Wistar大鼠随机分为8组,分别为2个对照组(空白组和生理盐水组)和6个染毒组(清洁、雾霾及沙尘暴3种不同天气的PM_(10)染毒组和PM_(2.5)染毒组),每组8只。用2015年3月—5月在北京南海子麋鹿苑采集的清洁、雾霾和沙尘暴3种不同天气的PM_(10)和PM_(2.5)制备悬液,分别采用气管滴入PM_(10)和PM_(2.5)悬液作为染毒组,空白对照组不做任何处理,生理盐水对照组采用气管滴注生理盐水。急性染毒24 h后处死大鼠。采集血液测定18个血常规指标,分析肺泡灌洗液(BALF)中转化生长因子-β1(TGF-β1)、乳酸脱氢酶(LDH)、总抗氧化能力(T-AOC)、白介素-6(IL-6)及肿瘤坏死因子-α(TNF-α)的含量,并在高倍显微镜下观察肺组织和气管病理形态变化。同时,对PM_(10)和PM_(2.5)中的水溶性离子、有机碳/元素碳、16种多环芳烃和7种重金属等元素进行了测定,并分析了各组分与大鼠生理病理指标的相关性。结果表明:清洁、沙尘暴天气的PM_(10)和雾霾天气的PM_(2.5)急性染毒导致大鼠白细胞系参数即免疫力显著下降。污染天气颗粒物染毒后大鼠BALF氧化炎症因子的改变表明呼吸系统受到感染:沙尘暴和清洁天的PM_(10)染毒均显著提高了TGF-β1,雾霾PM_(10)染毒后IL-6和LDH有一定程度升高。3种天气颗粒物染毒对肺和气管造成的组织病理伤害各有特点,但PM_(2.5)伤害程度普遍大于PM_(10)。染毒颗粒物粒径大小,其化学成分类别、浓度是造成大鼠血常规指标变化、氧化炎症反应和组织学病变的可能原因。

To investigate the health damage induced by inhalable particles in different polluted weather in Beijing,PM10 and PM2.5 were collected at the Nanhaizi Milu Park during clean, sand storm and haze weather conditions from March to May 2015. 64 male 8-week-old Wistar rats were randomly divided into 8 groups（8 for each group）,including two control groups（blank group and saline group） and 6 exposure groups（PM10 exposure group and PM2.5 exposure group with 3 different weathers of clean, dust storm and haze）. PM solutions were prepared and used for the exposure groups by tracheal instillation. The rats in the blank control group received no treatment, and in the saline control group was administered tracheal normal saline. All rats were sacrificed 24 hours after acute exposure. 18 routine blood parameters were measured, cytokines of TGF-β1, LDH, T-AOC, IL-6 and TNF-α in bronchoalveolar lavage fluid（BALF） were analysed, and the pathological changes of lung tissue and trachea were observed under high magnification microscope. At the same time, water soluble ions, OC/EC, 16 polycyclic aromatic hydrocarbons（PAHs）, and 7 heavy metals（Cu, Ni, Mn, Zn, Pb, As and Cr） in PM10 and PM2.5 were measured, and the correlations between the PM components and rat physiological and pathological parameters were analyzed. The results showed that acute PM10 exposure in both clean and sandy weathers, and PM2.5 exposure in haze weather resulted in a significant decrease in rat white blood cell parameters and immunity. Changes in oxidant and inflammatory factors in rat BALF after exposure to PM indicated that the respiratory system was infected, i. e.,PM10 exposure in dust storms and clean days both significantly increased the levels of TGF-β1, and levels of IL-6 and LDH were elevated at some extent after exposure to PM10 in haze days. The pathological damage of lung and trachea caused by PM under three kinds of weather conditions had its own characteristics, but the degree of PM2.5 injury was generally greater than that of PM10. The size of particles, their chemical composition and concentrations are the possible causes of routine blood parameter changes, oxidative inflammation and histological lesion in rats.