Comparative Evaluation Of Antidotal Efficacy Of 2-Pam And Hnk-102 Oximes During Inhalation Of Sarin Vapor In Swiss Albino Mice

Efficacy of two oximes treatments evaluated during inhalation of sarin vapor (LCt(50), 755.9mg/min/m(3)) in simulated real scenario in vivo. Majority of mice either became moribund or died within 1-2min during exposure to multifold-lethal concentrations of sarin vapor. Protection indices were determined by exposing to sarin vapor in two sessions, 1min exposure followed by treatments with or without HNK-102 (56.56mg/kg, im) or 2-PAM (30mg/kg, im) and atropine (10mg/kg, ip), and again exposed for remaining 14min. Protection offered by HNK-102 was found to be four folds higher compared to 2-PAM in the same toxic environment. Secondly, sub-lethal concentration of sarin vapor (0.8xLCt(50) or 605mg/min/m(3)), 24h post investigations revealed that the oximes could not reactivate brain and serum acetylcholinesterase (AChE) activity. The treatments prevented increase in protein concentration (p<.05) and macrophages infiltration compared to sarin alone group in broncho-alveolar lavage fluid. Lung histopathology showed intense peribronchial infiltration and edema with desquamating epithelial lining and mild to moderate alveolar septal infiltration in sarin and atropine groups, respectively. Noticeable peeling-off observed in epithelial lining and sporadic mild infiltration of epithelial cells at bronchiolar region in 2-PAM and HNK-102 groups, respectively. The oximes failed to reactivate AChE activity; however, the mice survived up to 6.0xLCt(50), proved involvement of non-AChE targets in sarin toxicity. Atropine alone treatment was found to be either ineffective or increased the toxicity. HNK-102, exhibited better survivability with lung protection, can be considered as a better replacement for 2-PAM to treat sarin inhalation induced poisoning.