A clinically relevant in vitro model for evaluating the effects of aerosolized vesicants

The chemical warfare vesicant sulfur mustard (HD) is a known toxic agent to the human respiratory tract and the major airways are considered to be a primary target of HD-induced injury. However, there is no consensus regarding which model systems are most appropriate for studying the effects of aerosolized vesicants on human airway epithelium. In this study, we evaluated the consequences of exposure of differentiated human respiratory epithelial cells in air-liquid interface to mechlorethamine (HN2), an HD functional analog. HN2 challenge was administered via the apical (air) interface over a wide dose range (20-400 microM) to differentiated HBE1 cells. Cultures were observed over 1-48 h for evidence of HN2-induced morphologic abnormalities as well as for possible cellular cytotoxicity, apoptotic changes, and induction of cytokine secretion. HN2 at concentrations of > or =200 microM caused disruption and denudation of the airway epithelial architecture within 24h of exposure. Moreover, HN2-induced cytotoxic and apoptotic changes in HBE1 cells in a dose- and time-dependent fashion. HN2 challenge also induced secretion of chemokines and proinflammatory cytokines including TNF-alpha, IL-1 alpha, IL-1 beta, IL-6, IL-8, RANTES, MCP-1, IP-10, G-CSF, GM-CSF and IL-15. These observations parallel those described in the lungs of HD-exposed victims and underscore the utility and potential applicability of this model to future mechanistic studies of vesicant-induced pulmonary injury.