Modifying effects of supplemental selenium and sulfur on cadmium toxicity in rats

Interactions among dietary supplements of selenium (Se), cadmium (Cd), and sulfur (S), and their effects on Cd toxicity in the cardiovascular system were explored in rats. Weanling male Sprague-Dawley rats were fed a Torula yeast-based diet in a 2³ factorial design, which provided two levels each of supplemental Se (0 and 0.5 ppm-mg/kg diet—as Na₂SeO₃), and S (0 and 2% as K₂SO₂). Supplemental Cd (0 and 25 ppm-mg/L as Cd (C₂H₃O₂)₂ · 2H₂O) was added to drinking water. Supplemental Cd induced cardiac hypertrophy only in rats not supplemented with Se. Selenium supplementation enhanced growth more markedly in Cd-fed rats than in rats not receiving Cd. Renal Cd content was increased by Cd feeding, but there was no significant effect of Cd feeding on hemoglobin or blood pressure. Supplemental Cd did not influence Se-GSH-Px activity in heart or kidney cytosol. Interactions between Se and Cd were not altered by S supplementation. These results suggest 1) that hypertension is not associated with increased kidney accumulation of Cd,per se; 2) a supplement of 0.5 ppm Se as selenite is sufficient to protect against Cd-induced reductions in Se-GSH-Px activity in heart and kidney cytosol; and 3) increased S intake does not compromise Se's protective effect against certain manifestations of Cd toxicity.