NF-κB信号通路在砷氟致家兔动脉组织炎症反应中的作用机制研究

Endemic arseniasis and endemic fluorosis are two significant public health issues in the world, which may result in adverse health effects to people and animals. The concurrent chronic poisoning with fluoride and arsenic is an emergent endemic disease in China. Epidemiologic and animal studies have shown that fluoride or arsenic exposure has been linked to atherosclerosis (AS). But there is limited information on the molecular mechanisms underlying their atherogenic toxicity and the joint action of these two elements. Inflammation is believed to play an important role in the pathogenesis of AS. We showed previously that arsenic and (or) fluoride could induce vascular endothelial activation and increase the expression of adhesion molecules on the mRNA and protein levels. NF-κB signaling pathway has been implicated in certain inflammatory diseases. We hypothesized that the inflammatory responses induced by arsenic and fluoride may be mediated by the NF-κB signaling pathway. To test the hypothesis, New Zealand White rabbits will be selected and treated with chronic fluorosis and (or) arseniasis. The expression of the molecules involved in inflammatory responses are to be detected on the mRNA and protein levels. Rabbit arterial endothelial cells (ECs) will be incubated with fluoride and(or) arsenic in vitro with or without the NF-κB inhibitor(PDTC). The expression of VCAM-1 will be determined to investigate the signal transduction mechanisms involved in the endothelial activation. The research would contribute to the understanding of vascular lesion pathogenesis induced by arsenic and fluoride. It could also provide a novel therapeutic target for the prevention and treatment of vascular injury induced by arsenic and fluoride.

地砷病和地氟病是严重危害人类及动物健康的地方性疾病，砷氟联合污染在我国广泛存在。流行病学和动物实验表明，砷和氟暴露与动脉粥样硬化（AS）发生有关，但对其联合中毒的效应及分子机理的研究还很少。炎症反应在AS发生发展中的作用受到越来越广泛的关注。课题组前期研究已证实，砷和氟可以引起家兔动脉内皮细胞活化表达粘附分子。基于NF-κB信号通路是重要的调节炎症反应的通路，我们推测"NF-κB信号通路参与了砷氟致家兔动脉组织炎症反应的发生"。为证实该假说，我们将建立砷氟单独及联合染毒动物模型，研究砷氟对动脉组织炎症相关因子表达的影响；建立兔主动脉内皮细胞体外培养体系，应用NF-κB抑制剂，以内皮细胞粘附分子（VCAM-1）表达为考察指标，研究砷氟致内皮炎症反应的信号调节通路。本研究将从新的角度揭示砷氟的血管毒性机制，并为其有效防治提供新思路和药物作用的靶点。

地砷病和地氟病是严重危害人类及动物健康的地方性疾病，砷氟联合污染在我国广泛存在。流行病学和动物实验表明，砷和氟暴露与动脉粥样硬化（AS）发生有关，但对其联合中毒的效应及分子机理的研究还很少。本课题在前期研究的基础上，从体内、体外实验两个方面研究砷氟对动物动脉组织炎症反应及NF-κB信号通路在砷氟引起的内皮细胞功能障碍中的作用机制。建立了砷氟单独及联合中毒动物模型，检测了砷氟暴露下家兔动脉组织病理学的改变及动脉组织炎症反应相关因子基因和蛋白表达的变化。建立了人脐静脉内皮细胞体外培养体系，研究砷氟暴露对体外内皮细胞氧化应激、炎症、凋亡的影响。采用Western blot技术检测了砷氟暴露下脐静脉内皮细胞NF-κB-p65、p-p65蛋白表达。应用NF-κB抑制剂PDTC预处理，检测通路下游基因产物VCAM-1蛋白质表达的变化，以证明NF-κB信号通路在砷氟致内皮炎症反应中的作用。结果表明，氟砷单独及联合可引起家兔动脉组织相关粘附分子、趋化因子、促炎细胞因子及巨噬细胞表面清道夫受体CD36表达上调，促进动脉粥样硬化发生。动脉组织病理学研究表明，各染毒组均表现不同程度的动脉损伤。砷氟可引起体外内皮细胞发生氧化应激，促进细胞内活性氧产生，NADPH氧化酶活性增高、基因表达上调，进而引起内皮细胞炎症因子表达、发生凋亡及NO产生减少等效应，呈现内皮细胞功能的障碍。砷氟暴露可引起内皮细胞NF-κB-p65、p-p65蛋白表达增加；应用NF-κB抑制剂PDTC预处理则砷氟暴露引起的内皮细胞粘附分子VCAM-1蛋白质表达下调，表明NF-κB信号通路参与了砷氟暴露引起的内皮细胞炎症反应。本研究从新的角度揭示了砷氟的血管毒性机制，并为其有效防治提供新思路和药物作用的靶点。