The impact of sublethal concentrations of Cu, Pb and Cd on honey bee redox status, superoxide dismutase and catalase in laboratory conditions

In this study, laboratory bioassays were performed to investigate the impact of sublethal concentrations of Cu (CuCl2: 1000, 100, 10 mg L−1), Pb (PbCl2: 10, 1, 0.1 mg L−1) and Cd (CdCl2: 0.1, 0.01, 0.001 mg L−1) on honey bee redox status and the activity of the main antioxidative enzymes and their gene expression. Our results show that exposure to these metals led to significant changes of gene expression, the levels of enzyme activity and redox status, but the effects are metal and dose dependent. In general, exposure of 48 h to given concentrations of Cu, Cd and Pb did not change the activity of antioxidative enzymes and the level of lipid peroxidation, with the exception of decreased activity of catalase at the lowest concentration of cadmium. Only lead produced increases in glutathione and thiol groups. Expression of genes for catalase and superoxide dismutase changed with exposure to cadmium and copper, whilst lead induced only expression of superoxide dismutase genes. The results from this study provide basic data for future research regarding the impacts of metal pollution on Apis mellifera and will be an important step towards a comprehensive risk assessment of the environmental stressors on honey bees.