苏州市独墅湖高教区PM2.5对大鼠呼吸系统急性损伤的研究
Acute Injury of Respiratory System in Rats Induced by PM2.5 Collected from Dushu Lake Higher Education Town in Suzhou
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摘要:目的 研究大气细颗粒物对大鼠呼吸系统急性损伤特征和可能的损伤机制。方法 将24只Wistar雄性大鼠随机分为4组,即对照组、PM2.5低、中、高剂量组(2.5 mg/kg、5.0 mg/kg和10.0 mg/kg)。以从苏州市独墅湖高教区某校区采集的PM2.5配制不同浓度的PM2.5悬液,急性染毒大鼠,采用气管滴注法连续染毒3 d。最后一次染毒结束24 h后处死实验动物,固定左肺组织并收集右肺的支气管肺泡灌洗液(BALF)。观察肺组织的病理学改变;检测BALF中乳酸脱氢酶(LDH),酸性磷酸酶(ACP),碱性磷酸酶(AKP),促炎因子TNF-α、IL-8,抗炎因子IL-4、IL-10水平;以流式细胞仪检测肺细胞线粒体膜电位(MMP),钙离子浓度(Ca2+),活性氧(ROS)含量变化。结果 肺组织病理学结果表明,PM2.5会引起肺部炎症反应,肺间质增宽,肺泡腔内分泌物增多,且随着染毒剂量的增加,病变程度有加重的趋势;大鼠肺泡灌洗液中酶、细胞因子基本没有变化,仅5.0 mg/kg和10.0 mg/kg PM2.5染毒后大鼠肺泡灌洗液中碱性磷酸酶(AKP)含量显著低于对照组;PM2.5染毒组钙离子浓度增高、线粒体膜电位降低,5.0 mg/kg PM2.5染毒组活性氧含量升高。结论 采自苏州市独墅湖高教区的PM2.5急性染毒可引起机体肺实质损伤,诱导氧化损伤,导致急性炎症性病变。Abstract:Objective To investigate the characteristics of acute respiratory system injury in rats induced by PM2.5 and its possible mechanisms.Methods Twenty-four Wistar male rats were randomly divided into four groups, including one control group and three PM2.5 exposure groups treated with endotracheal instillation of PM2.5 suspensions (2.5 mg/kg, 5.0 mg/kg and 10.0 mg/kg) for 3 consecutive days. PM2.5 samples were collected from a campus of Dushu Lake Higher Education Town in Suzhou. Rats were sacrificed 24 hours after the last treatment. The left lung of rats was fixed for pathological examination. Bronchoalveolar lavage fluid (BALF) from the right lung was collected for detecting the activity of enzyme (LDH, ACP, AKP), the level of cytokine related to both pro-inflammation (TNF-ɑ, IL-8) and anti-inflammation (IL-4, IL-10). The level of mitochondrial membrane potential (MMP), Ca2+ and reactive oxygen species (ROS) were measured by flow cytometer.Results Histopathological examination results indicated that PM2.5 induced pulmonary inflammatory response, pulmonary interstitial hyperplasia and increased alveolar cavities secretion in a dose dependent way. There were no obvious changes on the level of enzyme and cytokine both in the control and exposure groups except the activity of AKP in 5.0 mg/kg and 10.0 mg/kg groups, which decreased significantly compared with the control group. The level of Ca2+ increased while the MMP decreased in the lung cell of exposure groups compared with that of the control group.Conclusions Acute exposure of PM2.5 could induce parenchymal injury, inflammation and oxidative stress of lung in rats; PM2.5 were collected from Dushu Lake Higher Education Town in Suzhou.
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