Effects of calcium disodium EDTA and meso-2,3-dimercaptosuccinic acid on tissue concentrations of lead for use in treatment of calves with experimentally induced lead toxicosis.
OBJECTIVE
To compare the efficacy of calcium disodium EDTA (CaNa2EDTA) and meso-2,3-dimercaptosuccinic acid (DMSA) in reducing concentrations of lead in selected tissues for use in treatment of calves with experimentally induced lead toxicosis.


METHODS
19 sexually intact male Holstein calves that weighed 35 to 60 kg.


METHODS
Calves were randomly assigned to 1 of 5 treatment groups: group 1, control calves; group 2, lead only; group 3, lead and EDTA; group 4, lead and DMSA; and group 5, lead, EDTA, and DMSA. Calves in groups 2 to 5 were dosed daily with lead (5 mg/kg, PO) for 10 days. Doses of EDTA (100 mg/kg) and DMSA (25 mg/kg) were administered IV once daily for 4 consecutive days beginning on day 11. Effects of the chelators on lead concentrations in the liver, kidneys, testes, muscles, bones, and brain were compared among the various groups.


RESULTS
Compared with the effects of EDTA, DMSA greatly reduced lead concentrations in renal and hepatic tissues. We did not detect significant differences for the effects of EDTA or DMSA on lead concentrations in the testes; there was an adverse interaction of EDTA with DMSA that caused an increase in lead concentrations in the testes.


CONCLUSIONS
DMSA is much more effective than EDTA in removing lead from renal and hepatic tissues in calves. Use of DMSA in calves with lead intoxication appears to be a viable treatment option. Combining DMSA and EDTA as a treatment modality in calves did not offer any advantages.
Meldrum
James B
JB
Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061, USA.
Ko
Kam W
KW
D000818:Animals; D001842:Bone and Bones / Q000737:chemistry; D001923:Brain Chemistry; D002417:Cattle; D002614:Chelating Agents / Q000627:therapeutic use*; D004359:Drug Therapy, Combination; D004492:Edetic Acid / Q000627:therapeutic use*; D007668:Kidney / Q000737:chemistry; D007854:Lead / Q000493:pharmacokinetics*; D007855:Lead Poisoning / Q000188:drug therapy*; D008099:Liver / Q000737:chemistry; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry; D004113:Succimer / Q000627:therapeutic use*; D013737:Testis / Q000737:chemistry
D002614:Chelating Agents; D007854:Lead; D004492:Edetic Acid; D004113:Succimer