Induction of oxidative stress and DNA damage by chronic administration of naphthalene to rats

Naphthalene is a bicyclic aromatic compound that is widely used in various domestic and commercial applications including lavatory scent disks, soil f umigants and moth balls. Little information is available regarding the mech anism of naphthalene toxicity. We have assessed the oral, low dose (0.05 LD 50) chronic effects of naphthalene (110 mg/kg/day p.o. in corn oil) for 120 consecutive days on lipid peroxidation and DNA fragmentation in the liver and brain tissues of female Sprague-Dawley rats. The animals were sacrifice d on 0, 15, 30, 45, 60, 75, 90, 105 and 120 days of treatment. Maximum incr eases in hepatic and brain lipid peroxidation and DNA fragmentation were ob served between 90 and 105 days of treatment. Following administration of na phthalene for 90 days, approximately 1.4- and 1.3-fold increases in lipid p eroxidation were observed in the hepatic and brain tissues, respectively, w hile under the same conditions and time points 1.9- and 2.5-fold increases in hepatic and brain DNA fragmentation were observed, respectively. These r esults demonstrate that low dose chronic administration of naphthalene indu ces an oxidative stress resulting in tissue damaging effects that may contr ibute to the toxicity and carcinogenicity of naphthalene.