Comparative Experiment On The Lung Injury Induced By Fine Particulate Matter From Two Districts Of Shanghai

A large number of studies have shown that particulate matter associates with human health stronger than any other air pollutants. Compared with the coarse particles with aerodynamic diameter less than 10 micrometer (PM10), fine particulate matter with aerodynamic diameter less than 2.5 micrometer (PM2.5) has smaller size, the larger surface area, carrying a great amount of adsorbed toxic air pollutant and higher deposition and transference efficiency. Epidemiological studies have shown that PM2.5 is closely related to the rise of the incidence or mortality of respiratory diseases such as pneumonia, asthma. Respiratory disease daily mortality of residents living in China, the USA and the European rose 1.00%,1.78% and 1.00% with PM2.5 concentrations rising every 10μg/m3.Particulate matter is a mixture with complicated composition and its chemical composition depends on the surrounding environment, especially the influence of industry or transportation. Its toxicity, especially in a comparative point of view, was sometimes reported internationally but rarely in China. Therefore, toxicity and chemical composition of particulate matter gathered from two districts of Shanghai is to be compared through experiments with the purpose to explore its possible mechanisms.The first part analysed the chemical composition in PM2.5 from two districts of Shanghai in each season. Major soluble ions were tested by ion chromatography.17 elements were tested by inductively coupled plasma spectrometer. OC and EC were tested using Carbon Analyzer. And polycyclic aromatic hydrocarbons (PAHs) were tested by gas chromatography-mass spectrometry. The PM2.5 level in Baoshan was higher than that in Xuhui, speculating that it was associated with iron and steel enterprises.And the levels of PM2.5 were higher in winter and spring speculating the correlation with the coal combustion and atmospheric inversion phenomenon in winter. Major soluble ions occupied about 50% for the PM2.5 sample, the ions, SO42-, NH4+ and NO3-, Cl- as the main part of the ions, accounted for over 90% of the soluble ions. Eelements occupied less than 5%, TC occupied about 20%, and others were unknown matters. The concentrations of transition metals such as Zn、Cu、Ni、 V and soluble ions such as SO42-、NO3-、F-、Cl- in Baoshan PM2.5 were significantly higher than those in Xuhui PM2.5, indicating that Baoshan PM2.5 was greatly influenced by production activities of iron and steel industry.The levels of geological metals such as Ca、Al、Na、K、Mg in Xuhui PM2.5 were greater than those in Baoshan PM2.5, indicating that Xuhui PM2.5 was affected by dust. The levels of polycyclic aromatic hydrocarbons and organic carbon in Xuhui PM2.5 were higher than those in Baoshan PM2.5 speculating the correlation with traffic environment.Xuhui PM2.5 was more carcinogenic with more benzo [b] fluoranthene and benzo [k] fluoranthene, pyrene,1,12-benzopyrene.In addition, the chemical compositions of PM2.5 in different seasons were different. In summary, the chemical composition of PM2.5 in different districts of Shanghai in each season has been identified.The second part compared the lung injury of PM2.5 in each season collected from two districts of Shanghai through an animal experiment. PM2.5 was sampled from Baoshan and Xuhui districts of Shanghai in each season.150 SD (Sprague Dawley) rats were divided into three dosage groups (1.6,8.0, and 40.0 mg/kg body weight) and one saline control group of six rats each. Each group received intratracheal instillation once per day for three consecutive days. Twenty four hours after the last exposure, bronchoalveolar lavage fluid (BALF) was collected and analyzed for ingredient changes including lactate dehydrogenase (LDH), total protein (TP), tumor necrosis factor a (TNF-a), interleukin-6 (IL-6), and cell number. And then pulmonary pathological examination was done later. The size of rats, the lung coefficient and the concentrations of all parameters showed a dose-dependent manner. The effect on inflammatory markers was more strongly driven by high-dose PM2.5 exposure from Baoshan district than that from Xuhui district (P< 0.05). For high dose groups, the end weights of rats were lower after Baoshan PM2.5 exposure than after Xuhui PM2.5 exposure (P< 0.05). The larger lung coefficient was found after Baoshan particles exposure in high dose with no significance. For the Baoshan high dose groups, the levels of LDH were higher after spring particle exposure than after summer and autumn particle exposures (P< 0.05), and were also higher after winter particle exposure than after autumn particle exposure (P< 0.05). In contrast, for the Xuhui high dose groups, the lowest levels of LDH were found after autumn particle exposure (P< 0.05). Baoshan spring and winter PM2.5 exposure at high doses exhibited stronger toxic effects in producing IL-6 than summer and autumn particle exposure did, while Xuhui spring PM2.5 exposure at high doses produced more IL-6 than autumn exposure did(P<0.05).Baoshan spring PM2.5 exposure at middle and high doses exhibited the strongest toxic effects in producing TNF-α(P< 0.05), while Xuhui spring and winter PM2.5 exposure at high dose produced more TNF-α than summer and autumn exposure did (P< 0.05). The cell number increased more significantly in spring than in autumn in both Baoshan and Xuhui districts (P< 0.05). Pathological changes extended from bronchiole to alveolus and get worse with the raise of administration dosage. The fine particle matters from Baoshan district showed a stronger toxicity in terms of pulmonary inflammation than those from Xuhui district in high dosage group. Both districts showed seasonal variation in high dosage group.The third part combined with the result of former two parts. According to statistical analysis, whether the indicators of inflammation were related to chemical composition would be explored. The inorganic elements of Cu, Mn, Ni, zinc had a statistically significant positive correlation with nearly all the inflammatory responses. However Fe had a statistically significant positive correlation only with IL-6. Soluble ion of NO3- correlated positively with nearly all the inflammatory indexes. While Ca2+ positively significantly associated only with IL-6.This study hadn’t shown clearly that PAHs, OC, EC and TC associated with inflammatory factors in BALF.