In vitro Effects of Thimerosal and Its Metabolites on Cell Proliferation Kinetics and micronuclei frequency of Stimulated Human Lymphocytes (-S9/+S9)

Thimerosal is an ethylmercury-containing preservative in vaccines and biomedical preparations. Little is known about the genotoxicity reactions of thimerosal in human peripheral blood lymphocytes in vitro. In the study, short-term thimerosal toxicity was investigated in cultured human peripheral blood lymphocytes under conditions with and without S9 fraction. Cytokinesis-Block Micronucleus Test is a useful technique for the assessment of genotoxicity. Cultured human peripheral blood lymphocyte cells were incubated with 0.2µg/ml-0.6µg/ml concentrations of thimerosal for 72 h at 37oC under conditions without S9 fraction. Cultured human peripheral blood lymphocyte cells were incubated with 0.2µg/ml-0.6µg/ml concentrations of thimerosal for 3 h at 37oC under conditions with S9 fraction. Thimerosal induced the formation of micronuclei (MN) in a dose-dependent manner in the cytokinesis-blocked lymphocytes under conditions both with and without S9 fraction. Besides, thimerosal significantly decreased the cytokinesis block proliferation index in all the doses when compared with negative control, except at the dose of 0.2 μg/mL compared with negative control