The Oxidative and Morphological Effects of High Concentration Chronic Toluene Exposure on Rat Sciatic Nerves Omer Coskun, 1,4 Sukru Oter, 2 Ahmet Korkmaz, 2 Ferah Armutcu, 3 and Mehmet Kanter 1 (Accepted September 8, 2004) This study was designed to investigate the effects of chronic toluene inhalation in high con- centration on lipid peroxidation, antioxidant enzyme activities and ultrastructural changes in the sciatic nerves of rats. Male Wistar albino rats (150–250 g) were divided in two experi- mental groups: the control and the toluene treated group (n ¼ 10 for each). Toluene treat- ment was performed by inhalation of 3000 ppm toluene, in a 8 h/day and 6 day/week order for 16 weeks. Blood and tissue samples were obtained for biochemical and histopathological investigation. The blood and sciatic nerves were assayed for toluene by gas chro- matography. Toluene significantly increased blood and tissue malondialdehyde (MDA), and decreased tissue superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), but not tissue catalase (CAT) levels when compared with controls. Electron micrographs of sciatic nerve in the toluene group shows myelin destructions with onion-bulb and bubble form protrusion on the myelin sheath and axolemma border of myelinated axons. The area of injury on the myelin sheath were measured by Image-Pro Plus. Mean of the injury area were estimated 34% each myelin. These findings indicate that chronic toluene inhalation might be involved with free radical processes. KEY WORDS: Antioxidant enzymes; lipid peroxidation; sciatic nerve; toluene; ultrastructural. INTRODUCTION Toluene is a organic solvent heavily used in industry. It can cause severe central nervous system impairment (1,2) as well as in experimental investi- gations (3,4). Several studies, carried out with ani- mals, reported an uptake of inhaled toluene in blood and brain (5). Toluene is a hydrocarbon that is rapidly absorbed through the respiratory and gas- trointestinal tracts and, to a lesser extent, through the skin (6). Despite the widespread abuse of toluene and other solvents, the molecular sites of action of these compounds are largely unknown (7). More is known about the behavioral effects of these substances: tol- uene and other abused solvents produce effects simi- lar to that of central nervous system depressants. These effects include psychomotor impairment (8), excitation and then inhibition of locomotor activity (9), and loss of righting reflex and sedation (10). In addition, abused solvents possess anti-convulsant and produce ethanol-like discriminative stimulus 1 Department of Histology and Embryology, Faculty of Medi- cine, Zonguldak Karaelmas University, Zonguldak, Turkey. 2 Department of Physiology, Gulhane Military Medical Academy, Ankara, Turkey. 3 Department of Biochemistry and Clinical Biochemistry, Faculty of Medicine, Zonguldak Karaelmas University, Zonguldak, Turkey. 4 Address reprint request to: Omer Coskun, Zonguldak Karael- mas U ¨ niversitesi, Tp Fakultesi, Histoloji-Embriyoloji AD Zon- guldak- Turkey. Tel: +90-37225-77394; Fax: +90-37225-77395; E-mail: dromercos@yahoo.com 33 0364-3190/05/0100–0033/0 Ó 2005 Springer Science+Business Media, Inc. Neurochemical Research, Vol. 30, No. 1, January 2005 (Ó 2005), pp. 33–38 DOI: 10.1007/s11064-004-9683-6