Neurophysiological Changes in Rats Subchronically Treated with Styrene or Its Metabolites

Abstract

Neurophysiological Changes in Rats Subchronically Treated with Styrene or Its Metabolites: Junichi Misumi, et al. Department of Public Health and Hygiene, Oita Medical University—The purpose of this study was to clarify the causative agent(s) in the peripheral neuropathy induced by styrene. Styrene 600 or 300, and its metabolites; hippuric acid 600 or 300; mandelic acid 300; styrene oxide 100; mg/kg were subcutaneously injected into rats for 10 to 12 wk. The changes in maximum sensory conduction velocity (SCV), maximum motor conduction velocity (MCV), and motor distal latency (DL) in the rat's tail nerve were tested. Compared with the control group, decreases in MCV, SCV, and an increase in DL were observed in the rats injected with styrene 600, styrene oxide 100 and mandelic acid 300 mg/kg. No significant changes were found in the rats treated with hippuric acid 300 or 600 mg/kg. The MCV and SCV values in the styrene oxide 100 and mandelic acid 300 mg/kg groups were significantly lower, and DL values were significantly longer than those in the styrene 600 mg/kg group. It is presumed that the neuropathy caused by styrene is related to the neurotoxicity of its intermediate metabolites, namely mandelic acid and styrene oxide. It appears that the neurotoxicity of mandelic acid needs to be further evaluated in styrene‐produced neuropathy.