Arsenic-induced oxidative stress and its reversibility following combined administration of N-acetylcysteine and meso 2,3-dimercaptosuccinic acid in rats.

1. The present study examined whether arsenic induces oxidative stress in liver, brain and erythrocytes (RBC) based on the investigation of certain selected parameters. It also explored the possibility that combined administration of N-acetylcysteine (NAC) and meso 2,3-dimercaptosuccinic acid (DMSA) was capable of achieving better reversibility in the parameters indicative of arsenic-induced oxidative stress than individual treatment with either of these drugs. 2. Male rats were exposed to 100 p.p.m. sodium arsenite in their drinking water for 12 weeks (equivalent to 12 mg/kg As). The arsenic was then removed and rats were given NAC (1 mmol/kg per day), DMSA (1 mmol/kg per day) or a combination of the two, orally, once daily for 5 days. Animals not given arsenic and those given arsenic but not NAC or DMSA served as negative and positive controls, respectively. 3. Twelve weeks of arsenic exposure was found to deplete glutathione (GSH) levels, increase oxidized glutathione (GSSG) and promote malondialdehyde (MDA) production in both liver and brain samples. In addition to a significant reduction in RBC delta-aminolevulinic acid dehydratase (ALAD) activity and GSH levels, a marked elevation in MDA production may also contribute to arsenic-induced oxidative stress. 4. Treatment with either NAC or DMSA alone partially reversed arsenic-induced alterations in hepatic GSH and MDA, while only brain MDA levels responded favourably to these drugs. Only DMSA appeared to restore blood ALAD, while RBC MDA levels responded favourably to both drugs. Treatment with DMSA also produced an effective depletion of blood and hepatic arsenic concentrations. In the liver, most of these parameters were more effectively reversed by combined treatment with NAC and DMSA compared with the effects of either drug alone. 5. These results provide in vivo evidence of arsenic-induced oxidative stress in liver, brain and RBC and indicate that these effects can be mitigated by pharmacological intervention that encompasses combined treatment with NAC and DMSA.