ABSTRACT
OBJECTIVE: To determine the effects of 1-bromopropane( 1-BP) subacute inhalation on the expression of neuron specific enolase( NSE) and myelin basic protein( MBP) in plasma and brain tissue in male rats. METHODS: Specific pathogen free adult male Wistar rats were randomly divided into 4 groups with 12 rats in each group: the control group,the low-,medium- and high-dose groups with 1-BP exposure levels at 0,1 250,2 500 and 5 000 mg / m3,respectively. The rats were given continuous dynamic inhalation of 1-BP for 6 hours per day,5 days per week,for continuous 4 weeks. The rats were sacrificed at the end of exposure,9 rats from each group were randomly chosen and the blood from abdominal aorta was collected and the plasma was isolated. The plasma levels of NSE and MBP were measured by enzyme-linked immunosorbent assay. The whole brain,pallium,cerebellum and brainstem were isolated for detection of organ coefficient.The rest of 3 rats in each group were processed for histopathologic examination and the expressions of NSE and MBP were evaluated by immunohistochemistry. RESULTS: The organ coefficients of whole brain,pallium,cerebellum and brainstem in the high-dose group were higher than those in the control group [( 0. 754 ± 0. 056) % vs( 0. 663 ± 0. 035) %,( 0. 382 ±0. 037) % vs( 0. 339 ± 0. 021) %,( 0. 115 ± 0. 008) % vs( 0. 098 ± 0. 006) % and( 0. 213 ± 0. 018) % vs( 0. 183 ±0. 014) %,respectively,P < 0. 01]. The plasma NSE levels in the 3 exposure groups were lower than those of control group [( 7. 92 ± 0. 53) vs( 24. 73 ± 11. 44),( 9. 12 ± 2. 17) vs( 24. 73 ± 11. 44) and( 11. 10 ± 2. 84) vs( 24. 73 ±11. 44) mg / L,respectively,P < 0. 01]. The plasma MBP levels in all groups showed no statistical difference [( 2. 52 ±0. 70) vs( 2. 50 ± 0. 72) vs( 2. 47 ± 0. 66) vs( 2. 44 ± 0. 81) mg / L,P > 0. 05]. Histopathological examination showed that a few necrotic nerve cells were observed in hippocampus of rats in high-dose group. The expressions of NSE and MBP in brain tissue of rats in control,low- and medium-dose groups showed no significant difference. The down-regulated expression of NSE and MBP were only observed in cells of hippocampus of rats in the high-dose group. CONCLUSION: The1-BP induced neural toxicity was reflected in the function of central nervous system rather than in the structural morphology. The plasma NSE might be one of the effect biomarkers for monitoring 1-BP exposure.