Protection of human upper respiratory tract cell lines against sulphur mustard toxicity by hexamethylenetetramine (HMT).

1. Sulphur mustard ('mustard gas', HD) is a highly toxic chemical warfare agent which affects the skin and respiratory tract. The primary targets of inhaled HD are the epithelia of the upper respiratory tract. Hexamethylenetetramine (HMT) has been shown to protect human lung cells against HD toxicity and has also been shown to be effective in vivo against the chemical warfare agent phosgene. The ability of HMT to protect against the toxicity of HD was investigated in the human upper respiratory tract cell lines BEAS-2B and RPMI 2650. 2. HD was highly toxic to both cell lines, with LC50 values of 15-30 microM. HMT, at a concentration of 10 mM, was shown to protect the cell lines against the toxic effects of 20 microM and 40 microM HD. Results demonstrated that it was necessary for HMT to be in situ at the time of exposure to HD for effective cytoprotection. No protection was seen when cells were treated with HMT following exposure to HD, or where HMT was removed prior to HD exposure. 3. Results suggest that HMT may be effective prophylaxis for exposure to HD by inhalation.