Maganese retention in rat brain

Manganese retention was observed in brains and in several other tissues of female Wistar rats after the intratracheal instillation of an inorganic manganese compound: manganese dioxide. Two categories of rats, younger (180 to 200g) and older (330 to 350g), were divided into a control group, in which animals received vehicle only (0.5 mL physiological saline), and an experimental group, in which rats received a dose of 0.48 mg of Mn/kg body weight (in 0.5 mL saline), twice a week for 3 months, for a total dosage of 11.80 mg of Mn/kg body weight. At the end of the exposure period, manganese retention in selected rat organs, brain, liver, kidney, and lung, was analyzed using atomic absorption spectrophotometry. At the end of the 6-wk or 12-wk manganese dioxide exposure period, analysis of variance of the manganese retention results revealed significant differences between Mn-exposed and unexposed rats in brain, kidney, and lung tissues (p<0.01) for both experimental age categories. Moreover, at the end of the 12-wk exposure period, significant results (p<0.05) between younger and older rats were obtained for both brain and kidneys. In both types of tissue, the manganese retention in the younger group was higher than that in older animals.