Inhalation toxicity in mice exposed to sarin (GB) for 20-720 min

Area of Science:

• Toxicology
• Chemical Warfare Agents

Background:

• Historical sarin (GB) toxicity data primarily covers short exposures (<10 min).
• Understanding toxicity from longer exposures (1-12 h) is vital for personnel working in or near low-level chemical environments and for safety protocols regarding protective equipment removal.

Purpose of the Study:

• To determine the toxicity of sarin (GB) in mice for prolonged whole-body exposures ranging from 20 minutes to 12 hours.
• To evaluate how these longer exposure toxicity data align with established toxicological models like Haber's rule and the toxic load model.

Main Methods:

• Whole-body exposure of mice to sarin (GB) for durations of 20, 60, 180, 360, and 720 minutes.
• Calculation of Lethal Time-Concentration 50% (LCT50) and Lethal Concentration 50% (LC50) values for each exposure duration.
• Comparison of experimental data with predictions from Haber's rule (LCT50=CT) and a previously established toxic load model (CnT).

Main Results:

• LCT50 values obtained were 430, 540, 900, 1210, and 2210 mg.min m⁻³ for 20-, 60-, 180-, 360-, and 720-minute exposures, respectively.
• LC50 values obtained were 21.5, 9.0, 5.0, 3.4, and 3.1 mg m⁻³ for the respective exposure times.
• Toxicity data for exposures longer than 60 minutes did not follow Haber's rule or the toxic load model, showing progressively lower toxicity (higher LCT50/LC50 values) than predicted.

Conclusions:

• Sarin (GB) toxicity in mice for exposures between 3 and 12 hours does not adhere to Haber's rule or the toxic load model.
• The findings highlight the need for revised toxicological models to accurately assess risks associated with prolonged exposure to chemical warfare agents at lower concentrations.
• This data contributes to a broader multi-species effort to establish human toxicity estimates for extended exposure durations.