BACKGROUND:Dithiocarbamates can cause demyelination of axons in the peripheral nervous system.Its derivate,diethyldithiocarbamate,is cytotoxic,and causes olfactory mucosal damage and atrophy of the olfactory bulb.However,it is still unclear whether the myelin sheath of the lateral olfactory tract is affected by diethyldithiocarbamate. OBJECTIVE:To investigate the effects of diethyldithiocarbamate on the myelin sheath of the rat lateral olfactory tract.This was done by examining changes in myelin basic protein expression after diethyldithiocarbamate treatment. DESIGN,TIME AND SETTING:A randomized,controlled,animal study was performed at the Laboratory of the Department of Human Anatomy and Neurobiology,Xiangya School of Medicine, Central South University,China from July to November 2007. MATERIALS:A total of 72 Sprague Dawley rats were randomly assigned into a diethyldithiocarbamate group(n = 32),a solvent control group(n = 32),and a blank control group (n = 8).The diethyldithiocarbamate and solvent control groups were separately divided into 3-d, 7-d,14-d and 28-d survival subgroups,with eight rats in each.Diethyldithiocarbamate(Sigma, USA) and goat anti-myelin basic protein polyclonal antibody(Santa Cruz,USA) were used in this study. METHODS:Rats in the diethyldithiocarbamate and solvent control groups were subcutaneously injected with diethyldithiocarbamate(600 mg/kg) and 0.01 mol/L phosphate buffered saline (600 mg/kg) at the posterior neck,respectively.Rats in the blank control group received no treatment. MAIN OUTCOME MEASURES:Immunohistochemical staining and Western blot assay were used to measure myelin basic protein expression in the rat lateral olfactory tract. RESULTS:Following immunohistochemical staining,myelin basic protein was uniformly distributed in the rat lateral olfactory tract in the blank control and solvent control groups.Western blot assay showed 21.5,18,17 and 14 ku positive bands.No significant difference was found in myelin basic protein distribution and blot pattern,in the rat lateral olfactory tract,in the diethyldithiocarbamate group,following immunohistochemical staining and Western blot assay. Myelin basic protein expression gradually decreased at day 3,reached the lowest level at day 7, and gradually increased again at days 14 and 28. CONCLUSION:Demyelination is induced by diethyldithiocarbamate in the rat lateral olfactory tract in an early stage,followed by remyelination at later stages. BACKGROUND: Dithiocarbamates can cause demyelination of axons in the peripheral nervous system. Its derivate, diethyldithiocarbamate, is cytotoxic, and causes olfactory mucosal damage and atrophy of the olfactory bulb. Still, it is still unclear whether the myelin sheath of the lateral olfactory tract is affected by diethyldithiocarbamate. OBJECTIVE: To investigate the effects of diethyldithiocarbamate on the myelin sheath of the rat lateral olfactory tract. This was done by examining changes in myelin basic protein expression after diethyldithiocarbamate treatment. DESIGN, TIME AND SETTING: A randomized, controlled, animal study was performed at the Laboratory of the Department of Human Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, China from July to November 2007. MATERIALS: A total of 72 Sprague Dawley rats were randomly assigned into a diethyldithiocarbamate group (n = 32), a solvent control group (n = 32), and a blank control group (n = 8). The diethyldithiocarbamat e and solvent control groups were divided into 3-d, 7-d, 14-d and 28-d survival subgroups with eight rats in each. Diethyldithiocarbamate (Sigma, USA) and goat anti-myelin basic protein polyclonal antibody METHODS: Rats in the diethyldithiocarbamate and solvent control groups were subcutaneously injected with diethyldithiocarbamate (600 mg / kg) and 0.01 mol / L phosphate buffered saline (600 mg / kg) at the posterior neck, respectively. Rats in the blank control group received no treatment. MAIN OUTCOME MEASURES: Immunohistochemical staining and Western blot assay were used to measure myelin basic protein expression in the rat lateral olfactory tract. RESULTS: Following immunohistochemical staining, myelin basic protein was uniformly distributed in the rat lateral olfactory tract in the blank control and solvent control groups. Western blot assay showed 21.5, 18, 17 and 14 ku positive bands.No significant difference was found in myelin basic protein distribution and blot pattern, in the rat lateral olfactory tract, in the diethyldithiocarbamate group, following immunohistochemical staining and Western blot assay. Myelin basic protein expression gradually decreased at day 3, reached the lower level at day 7, and gradually increased again at days 14 and 28. CONCLUSION: Demyelination is induced by diethyldithiocarbamate in the rat lateral olfactory tract in an early stage, followed by remyelination at later stages.