Lead accumulation and metallothionein content in female rats of different ages and generations after daily intake of Pb-contaminated food.

Female Wistar rats of different ages (45, 90 and 140 days) and generations (mothers and offspring) were fed a feed containing 2.0mg of Pb kg-1 daily from weaning and the Pb accumulation was determined in different organs and in maternal milk, in addition metallothioneins (MTs) content was determined in the liver and kidneys. The results showed that Pb accumulation exhibited the following pattern: bone>liver>kidney>gut>blood cells>muscle>brain>ovary. Bones accumulated the most Pb in all animals, with its concentration increasing with age and prenatal exposure. Pb accumulation in the liver, kidney and blood cells, did not follow a consistent pattern with increasing age and our data did not indicate a relationship between the presence of MTs in liver and kidney and metal accumulation in these organs. However, in the offspring and with increasing age, Pb accumulated in more organs. Mothers fed with Pb produced contaminated milk, exposing their offspring to the metal via nursing Thus, increasing age and prenatal exposure increases susceptibility to Pb toxicity-induced damage.

Daily intake of lead in Wistar rats at different ages: Biochemical, genotoxic and physiological effects.

The effects of the daily intake of feed containing lead (2.0 mg Pb kg(-1)) were evaluated in 45 (Pb45) and 90 (Pb90)-day-old Wistar female rats. Compared to the respective control groups, Pb45 rats consumed more feed and showed greater weight gain, but these parameters returned to control values in Pb90 rats. Higher blood glucose levels were observed in both Pb groups, whereas plasma insulin concentrations were higher in Pb45 but lower in the Pb90 group. Liver glycogen content was lower only in the Pb90 rats. There were no changes in plasma cortisol and acetylcholinesterase activity in the brain. Hematological alterations were observed only in Pb90 rats, which showed lower hemoglobin levels. In the liver, Pb45 rats showed decreased catalase and glutathione peroxidase activities and increased glutathione reductase activity, but in the Pb90 group, glutathione levels were higher. Increased hepatic lipid peroxidation and DNA damage in the lymphocytes were observed in both Pb groups. These results indicate that the daily intake of Pb for different periods results in metabolic changes and in the establishment of oxidative and genotoxic damage in female rats.