Lethal acute lung injury and hypoglycemia after subcutaneous administration of monochloroacetic acid

Area of Science:

• Toxicology
• Environmental Health
• Pulmonary Medicine

Background:

• Cutaneous exposure to monochloroacetic acid (MCA) can induce acute lethal toxicity.
• While hepato-renal dysfunction is implicated, the precise mechanisms and primary organs responsible for MCA-induced mortality remain unclear.
• Respiratory failure is suspected as a potential cause of death in some reported MCA exposure cases.

Purpose of the Study:

• To investigate the dose-response relationship between MCA exposure and its toxic effects in rats.
• To determine the roles of hypoglycemia and lung injury in MCA-induced acute lethal toxicity.
• To identify the primary target organs contributing to mortality following MCA exposure.

Main Methods:

• Rats were subcutaneously administered varying doses of MCA (108, 135, or 163 mg/kg).
• Serum glucose levels, blood gases, and bronchoalveolar lavage fluid (BALF) parameters were analyzed at 2 and 4 hours post-exposure.
• Parameters assessed included lactate dehydrogenase (LDH) and total cell counts in BALF to evaluate lung injury.

Main Results:

• At 2 hours post-MCA administration, no significant pulmonary injury or hypoglycemia was observed.
• However, dose-dependent increases in BALF LDH and total cells were noted, indicating early lung damage.
• By 4 hours, severe hypoglycemia was evident, and significant alveolar gas exchange dysfunction was observed in the highest dose group (163 mg/kg).

Conclusions:

• MCA exposure induces significant lung injury and severe hypoglycemia in a dose- and time-dependent manner.
• The observed hypoglycemia and lung injury, particularly impaired alveolar gas exchange, are strongly associated with mortality.
• These findings suggest that hypoglycemia and pulmonary damage are critical factors in the acute lethal toxicity of monochloroacetic acid.