典型高原城市室内灰尘有机磷阻燃剂污染特征及其对人角膜上皮毒性效应机制

High detection frequency and rich abundance of organophosphorus flame retardants (OPFRs) in indoor dust have attracted the scientific community. Altitude has been demonstrated to be an important factor to influence the distribution of OPRFs in the indoor and outdoor air and dust. However, the pollution characteristics of OPFRs in the indoor dust from the typical plateau city and the adverse effects of OPFRs contaminated indoor dust on human corneal epithelium are still unknown. In this program, we will focus on household dust from a typical plateau city Kunming and aim (1) to elucidate the differences in the seasonal variation of OPFRs levels in household dust; and (2) to figure out the toxic effects and associated molecular mechanism of OPFRs contaminated dust on human corneal epithelium, and the relationship between the levels of OPFRs in dust and cell responses. To achieve above-mentioned goals, firstly, the household dust will be collected weekly or fortnightly from Kunming houses, the OPFRs levels in dust will be detected and the seasonal variability of OPFRs contamination in dust will be systematically analyzed. Secondly, a three-dimensional human corneal epithelium mimetic model (3D model) will be established and its functional verification will be conducted before use. Thirdly, the 3D model will be exposed to OPFRs contaminated dust in a liquid-air interface manner, classical toxicological assays combined transcriptome analysis will be employed to uncover the toxic effects and associated molecular mechanisms of household dust with different OPFRs contamination. Finally, the relationship between the OPFRs concentrations and adverse effects will also be investigated. The results could provide systematical information for understanding the OPFRs pollution characteristics of household dust in Kunming. In addition, our results would give us implications for opportunely preventing OPFRs contaminated dust-induced human corneal epithelium injury.

有机磷阻燃剂（OPFRs）在室内灰尘高频检出和高浓度存在引起了广泛关注，城市海拔是影响室内外灰尘中阻燃剂污染程度的重要因素，但对高原城市室内灰尘OPFRs污染特征和人角膜健康效应的研究鲜有报道。本项目以典型高原省会城市昆明主城区家庭灰尘为研究对象，拟解决如下两个科学问题：（1）灰尘中OPFRs污染特征和季节变化规律；（2）OPFRs污染灰尘对角膜上皮细胞的毒性效应机制及OPFRs污染程度与毒性效应发生的关系。研究拟通过对不同季节家庭灰尘连续收集分析，厘清OPFRs污染的季节变化特征；通过室内灰尘“气-液”界面暴露三维多层角膜上皮细胞模型，借助毒理学和组学手段阐明不同OPFRs污染程度灰尘对角膜上皮细胞的毒性效应和分子机制，并弄清OPFRs污染程度与毒性效应发生的相关性。研究成果可为系统了解高原城市室内灰尘OPFRs污染特征和有效防控高原城市室内灰尘暴露引起的人角膜健康风险提供科学参考。

有机磷阻燃剂（OPFRs）在室内灰尘高频检出和高浓度存在引起了广泛关注，城市海拔是影响室内外灰尘中阻燃剂污染程度的重要因素，但对高原城市室内灰尘OPFRs污染特征和人角膜健康效应的研究鲜有报道。本研究以典型高原城市昆明市家庭和办公室室内灰尘为研究对象，分析了其中9种有机磷阻燃剂的污染特征，并检测了家庭灰尘种8种重金属的污染情况；同时以人正常角膜上皮细胞为研究工具，借助分子生物学和组学手段，阐明室内灰尘中典型有机磷阻燃剂和重金属的角膜毒性效应和分子机制。结果发现：（1）昆明市研究区域中办公区域室内灰尘中9种典型OPFRs的含量为（436.40±66.49 ng/g）要显著高于家庭灰尘（163.16±28.70 ng/g），且TPP，TCPP，TBEP，TCEP含量较高；（2）家庭灰尘中重金属Zn > Mn > Cu > Pb > Cr > Ni > As > Cd。（3）TCPP+TCEP复合暴露人角膜上皮细胞后诱发细胞氧化应激，改变炎症因子和焦亡相关基因（NLRP3、Caspase-1、IL-1β、IL-18、GSDMD）表达，从而诱导细胞发生焦亡，并可能诱发干眼疾病发生；（4）磷酸三丁酯（TBP）及其代谢产物磷酸二丁酯（DBP）共存条件下会加剧其对人角膜上皮细胞的危害程度，其通过下调细胞周期蛋白依赖性激酶CDK4和CDK2使得人角膜上皮细胞发生S期细胞周期阻滞，通过Caspase家族及线粒体损伤相关信号通道导致细胞凋亡，基于此，我们提出仅仅研究目标污染物，而忽略代谢产物会导致健康风险评估或者毒性研究不准确；（5）室内环境浓度下Ni暴露，会降低人角膜上皮细胞活力，破坏细胞内氧化平衡，加重氧化损伤，最终通过ROS的上调导致人角膜上皮细胞凋亡；（6）铜锰复合暴露显著增强了彼此的毒性，能够通过上调NLRP3炎症小体的表达，激活Caspase-1及IL-1β，最终使凋亡执行基因Caspase-3的mRNA表达显著提高，揭示铜锰复合暴露能够通过Caspase-3通路导致细胞凋亡，损伤人角膜上皮功能，最终引起角膜疾病发生。.综上，室内灰尘中有机磷阻燃剂（如TCPP，TCEP，TBP，DBP）以及重金属（Ni, Cu和Mn）均可诱发角膜健康危害，特别与眼表疾病干眼、角膜炎等疾病有关，在后续的健康风险评估或危害研究中应考虑实际环境种的多种污染物共存的情况。