Protective effect of tannic acid on the brain of adult rats exposed to cadmium and lead

• The effect of tannic acid on the brains of rats receiving Cd and/or Pb was examined.
• Two experiments were carried.
• Tannic acid was administered ad libitum in the form of aqueous solutions.
• Heavy metals were administered ad libitum in the form of aqueous solutions or in feed.
• The best results were obtained in the 2%TA group.

Chronic exposure to Cd and Pb causes brain damage. Tannic acid (TA) is a very efficient chelator for metals. The effect of exposure to Cd and/or Pb and TA on the rats’ brain were studied. Two experiments were carried. In experiment no. 1 metals were administered with feed (7 mg Cd and 50 mg Pb/kg) and TA with drink (0, 0.5, 1, 1.5, 2 or 2.5% solutions). In experiment no. 2, rats received an aqueous solutions of [Cd (7 or 14 mg/L) or Pb (50 or 100 mg/L)] or 2% TA, alternatively every 7 days. In both experiments, TA had a positive effect only on reducing the accumulation of Cd. Exposure to metals resulted in an decrease of superoxide dismutase and catalase activity, whereas TA administration increased those. The results suggests that TA are more effective if taken parallel to food contaminated by Cd, and their effectiveness is higher if their intake is long-term.