Zinc, copper or magnesium supplementation against cadmium toxicity: An experimental study

Abstract

Cadmium (Cd) is currently one of the most important toxic metals in occupational and environmental toxicology. It causes adverse effects on kidneys, liver, lungs, bones, testes, etc, and is classified in group 1 of human carcinogens. However, the mechanisms of Cd toxicity, particularly the role in disturbances of bioelements, are still not clear. Furthermore, there is at present no clinically useful chelating agent for the treatment of cadmium poisoning. According to the available results on antagonism between Cd and certain bioelements it remains to be answered whether zinc (Zn), copper (Cu) or magnesium (Mg) supplementation could have a protective effect against cadmium toxicity. This chapter displays present knowledge on interactions between toxic metal cadmium and essential metals Zn, Cu and Mg accompanied by our own investigations on this topic. In this work the influence of supplemental Zn, Cu or Mg on Cd content in blood, urine, brain, liver, heart, kidneys, lungs, pancreas, spleen, muscles and bones in rabbits exposed to cadmium has been investigated. The rabbits were divided into 5 groups: control group; Cd group-animals treated per os for 28 days with 10 mg Cd/kg b.w./day. The other four groups received daily 10 mg Cd/kg b.m. and bioelements: Cd+Mg group - 40 Mg/kg b.w.; Cd+Zn group - 20 mg Zn/kg b.w.; Cd+Cu group - 10 mg Cu/kg b.w. The cadmium concentration was determined by atomic absorption spectrophotometry. Zn and Mg supplementation decreased blood Cd although no significant changes of cadmium level were observed in urine. Both bioelements caused significant decrease of cadmium content in kidneys, spleen and bones, while Zn treatment additionally reduced cadmium content in brain. On the contrary, copper even increased Cd level in blood, liver and heart. The obtained results indicate antagonism between Zn and Cd, as well as Mg and Cd. These findings confirm the beneficial effect of Zn and Mg on Cd content and thus open the possibility of a new approach to the therapy and prophylaxis of Cd intoxication. Anyhow, Mg supplementation has advantage over Zn as it has positive effect on Cd level in the organism, but contrary to Zn, induces no marked disturbances of investigated bioelements.