engleski

Oral exposure to cadmium and its interaction with iron and zinc in non-pregnant and pregnant rats

Cadmium is a pervasive, highly toxic environmental pollutant. General population is exposed to cadmium from food (grains, potatoes, leafy vegetables and seafood), contaminated water and cigarette smoke. Women have a greater cadmium body burden, as they are prone to microelement deficiencies during childbearing age. Specific anatomical changes and increased nutritional requirements during pregnancy enhance gastrointestinal absorption of not only essential, but also toxic metals and metalloids. Cadmium accumulates in mammalian internal organs, including placenta, and interacts with most essential elements. The aim of our work was to evaluate and compare the effects of oral cadmium exposure on cadmium, iron and zinc distribution in non-pregnant and pregnant rats and in the foetuses. Female (Wistar) rats were exposed to 50 ppm Cd as chloride in demineralised water (Cd-exposed) or to demineralised water alone (control) for 20 days. Pregnant rats were exposed from gestation day 1 through 20. The rats were then killed ; whole blood sampled and liver, right kidney, placentas, and whole foetuses dissected, weighed, and tissue samples prepared for microelement analysis by atomic absorption spectrometry. Blood, kidney and liver cadmium was higher and liver and kidney iron lower in pregnant than in non-pregnant Cd-exposed rats. Liver zinc increased in all and kidney zinc decreased only in pregnant Cd-exposed rats. Cadmium accumulation in the placentas was associated with decreases in placental zinc and foetal iron. Placental cadmium accretion may interfere with essential element transfer to the foetus. Increased cadmium and zinc retention in maternal organs and reduced foetal zinc and iron availability may compromise foetal growth and development in utero since mother womb is the first environment for unborn young. In conclusion, cadmium exposure causes more perturbations in essential microelements in tissues during pregnancy than out of pregnancy and disrupts their placental transport to the foetus.

cadmium; oral exposure; essential micronutrients; iron; zinc

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