Nitrite therapy improves survival postexposure to chlorine gas

Area of Science:

• Toxicology
• Emergency Medicine
• Pharmacology

Background:

• Chlorine (Cl₂) gas exposure can cause severe airway and systemic injury.
• Oxidative stress and inflammation contribute to chlorine gas toxicity.
• Effective, rapidly administered field therapeutics for chlorine exposure are needed.

Purpose of the Study:

• To evaluate the efficacy of nitric oxide repletion using nitrite via intramuscular injection for preventing chlorine gas toxicity.
• To determine therapeutic parameters for nitrite administration post-chlorine exposure.

Main Methods:

• Male C57bl/6 mice were exposed to 600 parts per million (ppm) chlorine gas for 45 minutes.
• 24-hour survival was assessed with or without postexposure intramuscular nitrite injection (10 mg/kg) at 30 or 60 minutes.
• Neutrophil accumulation and the effect of neutropenia on survival were examined.

Main Results:

• A single nitrite injection 30 or 60 minutes postexposure significantly improved 24-hour survival from approximately 20% to 50%.
• Survival was linked to reduced neutrophil infiltration in the airways.
• Neutropenic mice showed improved survival but lost the protective effect of nitrite therapy.
• Female mice were more susceptible to chlorine toxicity and less responsive to nitrite therapy.

Conclusions:

• Intramuscular nitrite injection is an effective therapeutic intervention for acute chlorine gas toxicity.
• This treatment strategy demonstrates potential for rapid administration in mass-casualty incidents.
• Further research may be needed to address sex-based differences in response to chlorine toxicity and nitrite therapy.