DNA damage in leukocytes of mice treated with copper sulfate

Single stranded DNA breaks induced by copper sulfate (CuSO₄) in mice has been studied in vivo using Alkaline Single Cell Gel Electrophoresis (Comet assay). Mice were administered orally with doses of 0, 1.25, 2.50, 5.00, 7.50, 10.00 and 12.50 mg/kg body weight (b.wt.) of CuSO₄ respectively. The samples of whole blood were collected at 24, 48, 72 h, first week and second week post-treatment and the assay was carried out to determine single strand DNA breaks as represented by comet tail-length. In addition, the sample was used to study the repair efficiency by incubating the samples with RPMI medium for 2 h. Results indicated a significant DNA damage at all the doses after treatment with CuSO₄ when compared to controls showing a clear dose-dependent response (p < 0.05). A gradual decrease in the tail-lengths from 48 h post-treatment was observed and by second week, the values returned to control levels at all doses. The study on the repair efficiency indicated that mice treated with all the doses of CuSO₄ showed decrease in mean comet tail-length indicating repair efficiency capacity but less when compared to those of controls. The study also reveals that comet assay is a sensitive and rapid method for detecting DNA damage caused by trace metals such as copper (Cu).