engleski

Suckling rats as experimental model for toxic metal exposure and selenium supplementation in the early period of life

Oral cadmium and mercury exposure during early life has been recognized as critical due to physiological specificities of the developing organism including increased gastrointestinal uptake and metal retention in the brain. Selenium as essential element may reduce retention of both toxic metals in adult animals, but its effects in newborns are not entirely elucidated. Only a low percentage of mothers exclusively breast-feed their children beyond 6 months and intake from milk accounts for very low portion of the total metal amount ingested. Our rat model has simulated newborn oral exposure from sources other than breastfeeding (additional nutrition, oral exploration, hand-to-mouth activity) using original methods for artificial feeding in suckling rats. Water solutions of cadmium or mercury (8 or 6 μmol/kg body weight a day in form of chloride) were administered two times a day (5 or 4 days) and in between all rats (Wistar) were allowed to suckle their own mother rats. Selenium solution (in form of sodium selenite) was given before and during cadmium (4+5 days) or mercury (3+4 days) exposure in equimolar dose to respective toxic metal. On postnatal day 15, suckling rats were anesthetised (Narketan/Xylapan) and urine, faeces, blood, and organs (after exsanguination from the abdominal aorta) were sampled to determine cadmium and mercury retentions. Selenium supplementation reduced cadmium levels in blood, brain, liver, and kidney and mercury levels in plasma, brain, and kidney. In conclusion, selenium can decrease retention of cadmium and mercury in the tissues of suckling rats and thus possibly diminish toxic metal effects.

suckling rat; cadmium; mercury; selenium supplementation; toxic metal retention

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