Phosgene Oxime Cutaneous Toxicity and Mechanisms to Identify Therapeutic Targets

在第二次世界大战期间储存的光气酮(CX；二氯仿)是一种强大的化学武器， 构成暴露的威胁；单独或与其他化学制剂一起。它是一种止痒或止痒的药剂 与发泡剂由于类似的破坏性质；尽管它造成的损害比其他 发泡剂由于其高活性的性质。尽管它是最臭名昭著的特种部队发泡剂 和恐怖主义利益，它是研究最少的化学战剂之一，没有具体的解毒剂可用。 关于其对人体皮肤组织和吸收的影响的信息有限，其作用机制是 未知。因此，明确的CX暴露动物模型对于研究CX的皮肤毒性和 开发有效的治疗方法。因此，这项建议的最终目标是开发相关的皮肤 环氧氯丙烷致小鼠皮肤损伤模型的建立 毒性效应，目的是为治疗干预和药物开发确定新的目标。 我们的初步数据显示，皮肤Cx蒸汽暴露在SKH-1无毛小鼠皮肤上(4分钟) 在30分钟内引起水肿、红斑、烫伤、荨麻疹和坏死，持续影响到8小时后 曝光。这些由皮肤CX暴露引起的临床损害的迅速发作与：a)和 表明DNA损伤反应的凋亡细胞死亡和P53磷酸化增加，b)和 与i)肥大细胞脱颗粒和促炎细胞因子增加相关的炎症反应 肿瘤坏死因子-α和环氧合酶-2，以及II)中性粒细胞浸润和髓过氧化物酶增加 级别。这些结果表明CX具有类似芥末的烷基化和亲核性质。 可导致DNA损伤和炎症反应的发泡剂。来自CX的皮肤荨麻疹类似于 经常引起的过敏性和非过敏性反应引起的荨麻疹，主要涉及炎症性反应 通过肥大细胞释放组胺。此外，CX辐射效应还伴随着扩张。 周围血管的红细胞在所有主要内脏的血管中都有强劲的激增，这可能会导致 血压骤降，缺氧死亡。基于这些发现，我们的假设是Cx激活 炎症和P53-DNA损伤通路是环磷酰胺致皮肤毒性的潜在主要因素 损害，并导致血管扩张和多个器官的血液充血，导致全身性 毒性和死亡率。提出检验这一假说的具体目标是：1)表征和建立CX- 皮肤暴露后诱导的在体啮齿动物皮肤损伤模型，并确定相关机制/S 以及2)检查CX皮肤暴露的全身毒性效应和相关死亡率。我们 预期我们的研究将建立急性CX暴露的皮肤和全身损伤生物标记物 可用于筛选治疗方案，以挽救CX的皮肤损伤和死亡率。

Stockpiled during World War II, Phosgene Oxime (CX; dichloroform oxime) is a potent chemical weapon that poses a threat of exposure; both, alone and with other chemical agents. It is an urticant or nettle agent grouped with vesicating agents due to similar damaging properties; although, it causes more severe damage than other vesicants due to its highly reactive nature. Even though it is the most notorious vesicant with special military and terrorist interests, it is one of the least studied chemical warfare agents with no specific antidote available. Information on its effect on human dermal tissue and absorption is limited, and its mechanism of action is unknown. Well defined animal models of exposure to CX are thus essential to study its skin toxicity and for the development of effective treatments. Thus, the ultimate goal of this proposal is to develop a relevant cutaneous CX exposure mouse injury model to elucidate mechanisms of skin damage by CX and examine its systemic toxic effects with the objective of identifying novel targets for therapeutic intervention and drug development. Our preliminary data show that cutaneous CX vapor exposure (4 min) on to the SKH-1 hairless mouse skin causes edema, erythema, blanching, urticaria and necrosis within 30 min with sustained effects till 8 h post- exposure. The rapid onset of these clinical lesions from cutaneous CX exposure were associated with: a) an increase in apoptotic cell death and p53 phosphorylation indicating a DNA damaging response, b) an inflammatory response associated with i) mast cell degranulation and increase in pro-inflammatory cytokine tumor necrosis factor-α and cyclooxygenase-2, and ii) neutrophil infiltration and an increase myeloperoxidase levels. These results suggest that CX possesses alkylating and nucleophilic properties resembling mustard vesicants that can cause DNA damage and an inflammatory response. The skin urticaria from CX resembles urticaria from frequently caused allergic and non-allergic reactions involving an inflammatorily response mainly via histamine release from mast cells. Additionally, the CX-exposure effects were accompanied with dilatation of peripheral vessels with a robust surge in RBCs in vessels of all the major internal organs, which could cause sudden blood pressure fall, hypoxia and death. Based on these findings, our hypothesis is that CX activates inflammatory and p53-DNA damaging pathways that are potential major contributors of CX-induced skin toxic lesions, and that it causes vasculature dilation and blood congestion in multiple organs resulting in systemic toxicity and mortality. Specific aims proposed to test this hypothesis are: 1) Characterize and establish CX- induced in vivo rodent skin injury model following its cutaneous exposure, and identify associated mechanism/s of action; and 2) examine systemic toxic effects and related mortality from CX cutaneous exposure. We anticipate that our studies would establish skin and systemic injury biomarkers of acute CX exposure that can be employed for screening therapies for the rescue of skin injuries and mortality by CX.