Chronic manganese oxide ingestion in rats: hematological effects

Hematological values were studied in Long Evans rats after chronic exposure to manganese oxide (Mn3O4). Data were obtained at selected ages from the P0 through the F2 generation. Effects of exposure to Mn3O4 during Fe deficiency were determined by placing half of the animals on a low-Fe diet (20 mg/kg) while the other half were maintained on a normal-Fe diet (240 mg/kg). Animals treated with Mn3O4 and maintained on a normal-Fe diet showed little variation from controls through 100 d of age. However, animals (24-100 d of age) maintained on a low-Fe diet and receiving Mn treatment during the prenatal and postnatal periods developed microcytic anemia. Irrespective of the dietary Fe level, serum creatinine levels decreased in the groups receiving 400 and 1100 ppm Mn while serum Ca and P levels increased in the group receiving 1100 ppm Mn at 100 d of age. Serum values for lactate dehydrogenase, alkaline phosphatase (100 d of age), and serum glutamic-oxaloacetic transaminase (224 d of age) were elevated for all animals on low-Fe diets. Globulin, albumin (100 d of age), and glucose (224 d of age) levels were depressed in all low-Fe groups.