Objective To compare the toxicity of fine particulate matters (PM2.5) in each season collected from different districts of Shanghai through an animal experiment.
Methods PM2.5 was sampled from Baoshan and Xuhui districts of Shanghai in each season.Sprague Dawley rats were divided into three PM2.5 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) were collected and analyzed for ingredient changes including lactate dehydrogenase (LDH),total protein (TP),tumor necrosis factor α(TNF-α),interleukin-6(IL-6),and cell number.
Results The concentrations of all parameters increased in a dose-dependent manner.The effect was more strongly driven by high-dose PM2.5 exposure from Baoshan district than that from Xuhui district (P < 0.05).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 (P<0.05),while Xuhui spring PM2.5 exposure at high dose 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).
Conclusion The fine particle matters from Baoshan district show a stronger toxicity in terms of pulmonary inflammation than those from Xuhui district in the same dosage group.Both districts show seasonal variations.
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