The therapeutic potential of thiamine for treatment of experimentally induced subacute lead poisoning in sheep

Lead poisoning remains a serious problem in veterinary and human medicine. A number of lead chelators have been used for treatment of lead intoxication, but none of them is completely effective to remove lead from all organs. Therefore, alternatives for the treatment of lead poisoning are required. In this study, the efficacy of thiamine on blood and tissue lead contents was evaluated in subclinical lead toxicosis in sheep. Nine female sheep weighing 25–29 kg were orally receiving a daily dose of 80 mg/kg body weight of lead acetate for 5 days. Then, the animals were assigned into two groups. Group 1 did not receive any further treatment and was used as the control group, and group 2 was treated intravenously by 25 mg/kg body weight of thiamine twice daily for 7 days. Within 1 day following treatment, in the treated group, blood lead level (mean 243.5 μg/l) was significantly (P < 0.05) lower than that in group 1 (mean, 518.16 μg/l). Thiamine treatment significantly reduced ovary lead content. A significant reduction of serum zinc concentration was also observed in thiamine treated animals. These results suggest that thiamine might have some therapeutic effects on lead poisoning, but the zinc status of depletion should be considered during long periods of treatment.