Biochemical changes in the central nervous system of rats exposed to 1-bromopropane for seven days

Abstract

1-Bromopropane is used widely as an alternative to ozone-depleting solvents. The neurotoxic effects of this agent have been described in humans and experimental animals. Here we investigated the underlying mechanisms of the neurotoxic effects of 1-bromopropane by examining the initial biochemical changes in the central nervous system. Four groups of 9 Wistar male rats each were exposed to 200, 400, or 800 ppm 1-bromopropane or only fresh air, 8 h per day for 7 days. At the end of the experiment, the cerebrum, cerebellum, brain stem and lumbar enlargement of the spinal cord were dissected out from each rat (n = 8) for biochemical analyses. Morphological examinations of the nervous system were performed in the remaining rat of each group. 1-Bromopropane dose-dependently decreased neurospecific γ-enolase, total glutathione, and nonprotein sulfhydryl groups in the cerebrum and cerebellum. Creatine kinase activity decreased dose-dependently in the brain and spinal cord. Histopathological examination showed swelling of preterminal axons in gracile nucleus and degeneration of myelin in peripheral nerves. Our results of low levels of γ-enolase suggested that 1-bromopropane might primarily cause functional or cellular loss of neurons in the cerebrum and cerebellum. Glutathione depletion or modification to functional proteins containing a sulfhydryl base as a critical site might be the underlying mechanism of 1-bromopropane neurotoxicity.