Screening of the chemoprotective effect of 13 compounds and their mixtures with sodium 2-mercaptoethanesulfonate against 2-chloroethyl ethyl sulfide.

2-chloroethyl ethyl sulfide (CEES) is a vesicant agent, commonly referred to half mustard due to its ability to form monofunctional adducts with DNA. In this study, we evaluated the chemoprotective potential of 13 compounds and their mixtures with sodium 2-mercaptoethanesulfonate (MESNA) against CEES-induced geno- and cytotoxicity in human lung cell line A-549. MESNA, L-glutathione (GSH), thiourea, sodium thiosulfate, hexamethylenetetramine, 4-acetamidophenol, asoxime dichloride (HI-6), N-acetyl-L-cysteine (NAC), sodium pyruvate, myo-inositol, 3-aminobenzamide (3-AB), nicotinamide, and Nω-nitro-L-arginine methyl ester hydrochloride and combinations of these compounds with MESNA were applied 30 min before CEES. DNA alkylation was measured using modified comet assay 1 and 24 h after the exposure. Cell viability was determined using MTT assay at 24 and 72 h. The mono-therapeutical approach identified MESNA and GSH to provide significant chemoprotection. NAC and 3-AB supported DNA damage repair, while cell viability remained unaffected. Mixtures of GSH or NAC with MESNA showed protective synergism against DNA damage. Other compounds or their combinations with MESNA failed due to the potentiation of CEES-induced cytotoxicity. The chemoprotection against CEES remains limited; however, the combination of substances can provide protective synergy and may represent a promising strategy in the treatment of accidental exposure to monoalkylating agents.