Genotoxicity and oxidative stress induced by cadmium and zinc in the planarian, Dugesia dorotocephala

Abstract

This study sought to determine the DNA damage, and the lipoperoxidative effect, as well as changes in the superoxide dismutase (SOD) and catalase (CAT) activities induced by CdSO4 (Cd), and ZnSO4 (Zn), in addition to two different mixtures of the metals. Planarian Dugesia dorotocephala collected in the Ignacio Ramirez reservoir, México, adapted to laboratory conditions, and exposed to the metals in a controlled system was used. Initially, LC50 at 96 h of exposure was determined and the result obtained were 0.69 mg/L for Cd, 11.99 mg/L for Zn, 10.28 mg/L for mix 1, and 8.11 mg/L for mix 2. Then, the comet assay showed a DNA damage increase induced by Cd (0.13 and 0.2 mg/L) as high as 94% over the control level; the effect by Zn (from 0.2 to 2.7 mg/L) was clearly lower, although statistically significant with the high concentrations tested. As regards the two mixtures, we observed a concentration dependent increase. Similarly, in respect to lipoperoxidation, we found a strong effect by Cd, a slight effect by Zn, and a concentration dependent effect induced by the mixtures. Finally, the activity of the tested enzymes was modified by the metals in relation to the concentration applied.

Keywords: Zinc, cadmium, planarian, DNA damage, oxidative stress

African Journal of Biotechnology Vol. 12(25), pp. 4028-4038