Evaluation of mutagenic effects of formocresol: detection of DNA-protein cross-links and micronucleus in mouse bone marrow.

Objective: The genotoxic potential of formocresol was assessed by comet assay on human peripheral blood lymphocytes and in vivo micronucleus in mice.

Study Design: Peripheral blood lymphocytes, obtained from healthy donors, were exposed directly with different dilutions of formocresol for 45 minutes at 37 degrees C. To verify the possibility of formocresol to induce DNA-protein cross-links, treated lymphocytes were incubated with proteinase K. Micronucleus test was performed on male Swiss mice treated with several dilutions of formocresol by single intraperitoneal injection. After treatment, bone marrow was sampled 24 and 48 hours after formocresol administration.

Results: Formocresol did not produce detectable DNA damage as evaluated by comet assay. However, after proteinase K exposure, a dose-dependent increase of DNA migration was observed. Formocresol induced a significant increase in micronucleus frequencies at the highest dilution only at 24 hours after administration.

Conclusion: Formocresol induced DNA-protein cross-links and an increased frequency of micronucleus.