The influence of N-acetyl
cysteine (NAC), an
antioxidant, on the therapeutic efficacy of meso-2,3-dimercaptosuccinic
acid (
DMSA), a hydrophilic, and its
ester, monoisoamyl 2,3-dimercaptosuccinate (MiADMS), a lipophilic, both soft tissue lead mobilizers, was investigated in lead-preexposed rats. The subsequent treatment of lead-exposed animals with
DMSA, MiADMS, or NAC reversed the lead-induced alterations in blood
delta-aminolevulinic acid dehydratase,
catalase,
malondialdehyde (MDA),
reduced glutathione,
oxidized glutathione, and brain MDA levels. The combined treatment with
DMSA and NAC was more effective than that with MiADMS and NAC in enhancing the restoration of all these parameters indicative of lead-induced oxidative stress. These reversals were consistent with the lead-removing ability of
DMSA and MiADMS but not that of NAC. As the reversal of these parameters by NAC was independent of its lead-mobilizing capability, this ought to be mainly due to its strong
antioxidant property. The increase in blood and brain
zinc levels upon lead exposure appears to be the result of the redistribution of endogenous
zinc due to lead. Subsequent treatment with
DMSA, MiADMS, NAC, or their combination decreased the brain
zinc as its excretable complexes with a transient increase in blood
zinc level. The ideal treatment of
lead poisoning seems to be a combination of a lead
chelator and an
antioxidant.