The Protective Role of Thiola against the Genotoxic Effect of Potassium Dichromate in Mice in vivo

Abstract

The genotoxic effect of hexavalent potassium dichromate (K₂Cr₂O₇) was investigated in mice in vivo using sister chromatid exchange (SCE) and chromosomal aberration analysis. K₂Cr₂O₇ induced a significant increase in the frequency of SCE's after intraperitoneal (i.p.) treatment with the doses 6, 12, 24 mg kg^-1b.wt. which correspond to 1/8, 1/4 and 1/2 of the experimental LD₅₀. The lowest tested dose 3 mg kg^-1b.wt. had no effect with respect to SCE's and its effect reached 6.57 ± 0.36/cell compared with 5.80± 0.55/cell for the control. The frequency of SCE's reached 9.03 ±0.20 after treatment with the highest tested dose of K₂Cr₂O₇, a value which is less than that induced by mitomycin C (13.10 ± 0.40) as the positive control. Thiola at the concentrations of 20 and 50 mg kg^-1b.wt. had moderate but non-significant effect for minimizing the frequency of SCE's induced by different doses of K₂Cr₂O₇.
With respect to chromosomal aberrations, all the tested concentrations of K₂Cr₂O₇ (3, 6, 12, 24 mg kg^-1b.wt.) induced a significant increase in the percentage of chromosomal aberrations in mouse bone marrow as well as in mouse spermatocytes 24 h after single i.p. treatment. The incidence of chromosomal damage increased significantly with increasing the dose. However mitomycin C induced higher effect. The results also show that the pretreatment with thiola at the dose of 50 mg kg^-1b.wt. significantly reduced the percentage of chromosomal aberrations induced by K₂Cr₂O₇ in all the treatment groups and the results confirm the protective role of thiola which has been proved previously against the genotoxicity of some mutagens.