Mitochondrial effects of low-level cadmium in rats: interaction with zinc.

Abstract

Male Sprague-Dawley rats were treated with sodium or cadmium (Cd) 4 acetate (25 μg Cd per kg body weight) orally 5 times a week for 6 weeks. A second group of animals was repeatedly injected with zinc sulphate (6 and 12 mg zinc (Zn) per kg ip) with or without Cd gavage. Cadmium treatment alone yielded no obvious toxic effects as evidenced by serum constituents or animal weight gain. Similarly, Zn injection did not affect these criteria. Zinc injection increased metallothionein in liver and kidneys and increased renal Cd. Cytosolic sorbitol dehydrogenase was not influenced by either cadmium, Zn or Cd + Zn exposure. However, individual Cd gavage decreased mitchochondrial cytochrome c oxidase in liver by 50%. This was partly protected by Zn. Hepatic adenosine triphosphatase (ATPase) was not affected by any of the treatment regimens. However, renal ATPase was inhibited by combined Cd + Zn administration. The data suggest subcellular toxic effects due to treatment with low Cd doses as evidenced by the decrease in hepatic cytochrome c oxidase. Simultaneous Zn injection may reduce this effect of Cd in liver. However, the treatment of rats by low level Cd gavage combined with zinc administration impairs the animals' health as shown by weight loss.