Cobalt Bioaccumulation in Mouse Blood Plasma and Liver

ABSTRACT

Heavy metals such as cobalt are shown to accumulate in various organs of humans and animals. Oral exposure of immature mice to cobalt compounds (cobalt chloride and cobalt-EDTA) led to significant increase in cobalt (II) concentration in blood plasma and liver. Pregnant balb/c mice in late gestation were subjected to cobalt chloride (CoCl₂.6H₂O) or cobalt EDIA (Co-EDTA) treatment at daily doses of 75 mg/kg or 125 mg/kg which continued until day 30 of the newborn mice. Cobalt salts were dissolved and obtained from drinking tap water. Pure tap water was used as control. Mice were maintained in individual standard hard bottom polypropylene cages to ensure that all experimental animals obtained the required dose of cobalt salts. The newborn pups were sacrificed on days 18, 25 and 30 which correspond to different stages of development. Mice were weighed weekly and the experimental cobalt concentration was adjusted accordingly. Blood plasma and liver were used for measuring cobalt bioaccumulation. Cobalt (II) compounds showed differential bioaccumulation: higher concentrations were measured in the plasma compared to those measured in the liver. The effect depended on the type of compound used, dose, time duration as well as on the age of the experimental animals. Higher metal concentrations were detected in samples of mice treated with cobalt chloride compared to the samples exposed to Co-EDTA. The results indicate that day 18 mice are more sensitive to chronic exposure to cobalt compounds in high doses. Cobalt(II) concentrations in blood plasma may be used as a useful marker for diagnosing chronic exposure to cobalt compounds.

Keywords:

• cobalt compounds
• bioaccumulation
• mice
• blood plasma
• liver