Pyrogallol-associated dermal toxicity and carcinogenicity in F344/N rats and B6C3F1/N mice

Area of Science:

• Toxicology and Carcinogenesis
• Dermal Exposure Studies
• Rodent Models

Background:

• Pyrogallol (CAS No. 87-66-1), a benzenetriol, has historical use as a hair dye and current industrial applications.
• Limited toxicity and carcinogenicity data necessitated evaluation by the National Toxicology Program (NTP).

Purpose of the Study:

• To determine the toxicity and carcinogenicity of pyrogallol following dermal administration.
• To assess long-term effects through two-year rodent studies.

Main Methods:

• Three-month and two-year dermal toxicity studies were conducted in male and female F344/N rats and B6C3F1/N mice.
• Animals were administered pyrogallol in ethanol at various doses (up to 150 mg/kg for rats, 600 mg/kg for mice in subchronic studies; 5, 20, 75 mg/kg in chronic studies).
• Histopathological examination of tissues, particularly at the site of application, was performed.

Main Results:

• Significantly increased non-neoplastic lesions at the application site were observed in all pyrogallol-dosed rats and mice in both studies.
• Survival of female mice at the highest dose (75 mg/kg) was significantly reduced.
• Carcinogenic effects were observed, including squamous cell carcinoma at the site of application in female mice and potential tumor development in male mice.

Conclusions:

• Pyrogallol induced significant non-neoplastic skin lesions in both rats and mice.
• Pyrogallol is carcinogenic in female mice and potentially carcinogenic in male mice following dermal exposure.
• Findings highlight the need for caution regarding pyrogallol's dermal application and industrial use.