经口摄入微塑料致小鼠肺部炎性损害及其机制初探

Preliminary study on pulmonary inflammatory damage and its mechanism in mice induced by oral ingestion of microplastics

目的 研究微塑料(MPs)经口摄入途径对小鼠肺组织的影响,并初步探索其影响机制。方法 采用聚苯乙烯微塑料(PS-MPs)模拟环境中MPs。将Balb/c雄性小鼠随机分为3组:对照组(Control)、0.05μm和0.5μm的MPs实验组,设计小鼠发育期和成熟期两个阶段暴露剂量。在发育期分别灌胃0.05μm、0.5μm MPs(0.3 mg/d),连续4周,进入成熟期,将剂量改为0.6 mg/d,再持续8周。对照组灌胃同体积蒸馏水,所有小鼠在16周时被处死。HE染色观察肺组织形态;分析PanglaoDB数据库中小鼠肺组织中表达NLRP3的细胞簇;免疫印迹法测定肺组织中NLRP3炎症小体相关蛋白的表达。结果 HE染色肺组织结果显示,0.05μm和0.5μm MPs组均能诱导小鼠肺组织炎性损害;PanglaoDB数据库中肺组织表达NLRP3的细胞簇为巨噬细胞;免疫印迹法检测肺组织样本结果显示,相比Control组,微塑料组小鼠肺组织蛋白表达均有增加趋势,但仅有0.05μm MPs实验组中蛋白表达有统计学意义(P<0.05)。此外,与0.5μm MPs组相比,0.05μm MPs实验组小鼠肺组织中的蛋白表达水平显著升高(P<0.05)。结论 经口摄入微塑料可能过度激活NLRP3炎症小体引发肺脏炎性损害。同时,针对0.05μm和0.5μm的微塑料,粒径越小对肺的炎性损害越严重。

Objective To study the effects of oral ingestion of microplastics(MPs)on lung tissue in mice and explore the mechanism.Methods Firstly,Polystyrene microplastics(PS-MPs)were used to simulate MPs in the environment.Balb/c male mice were randomly divided into three groups:control group,and 0.05μm and 0.5μm MPs groups.The exposure doses of the mice were designed as follows:MPs of 0.05μm,0.5μm(0.3 mg/day)was given orally for 4 consecutive weeks at the puberty stage,and the dose was changed to 0.6mg/day for another 8 weeks at the maturity stage.The control group was given the same volume of distilled water,and all mice were sacrificed at the 16th week.Then,HE staining was used to observe lung morphology,and the cell clusters expressing NLRP3 in lung samples of mice in PanglaoDB database were analyzed.Finally,the expression of NLRP3 and Caspase-1 in lung samples were determined by Western blotting.Results HE staining of lung samples showed that MPs group of 0.05μm and 0.5μm could induce inflammatory injury to lungs of mice.The cell clusters expressing NLRP3 are macrophages in lung samples of mice in PanglaoDB database.Meanwhile,the results of Western blot showed that:compared with the control group,the protein expression in the lung tissue of mice in the MPs groups had an increased trend,but only the 0.05μm MPs group had statistic difference(P<0.05).In addition,compared with the 0.5μm MPs group,the protein expression level of the 0.05μm MPs group was significantly increased(P<0.05).Conclusion Oral administration of MPs may promote the activation of NLRP3 inflammasome and cause the inflammatory damage to lung.For 0.05μm and 0.5μm MPs,the smaller the particle size,the more serious inflammatory damage to lung.