| Objective To explore the effects of1-bromopropane (1-bromopropane,1-BP) on ionotropic glutamate receptor subunits NR2B and GluR2in rats’brain, in purpose of investigating the mechanisms of the neurotoxicity induced by1-BP.Methods1. To establish1-BP sub-acute inhalation model Forty-eight male specific pathogen-free (SPF) adult Wistar rats were randomly divided into4groups (control group, low concentration group, medium concentration group and high concentration group) of12each. Four groups of rats were exposed to designed concentrations of1-BP at0mg/m3(fresh air),1250mg/m3,2500mg/m3and5000mg/m3in a dynamic inhalation chamber system,8hours a day,5days a week, for4consecutive weeks. The actual concentrations of1-BP vapor in the chambers were sampled and tested daily. The performances and behaviors of the rats were observed everyday, while the rats were weighed every3days. Rats were sacrificed at the end of the sub-acute exposure, the brain, heart, liver and other organs were removed for the following tests.2. Three rats per group were selected to detect the distribution of NR2B and GluR2in rats’brain by the method of immunofluorescence.3. Nine rats per group were selected to detect the protein and mRNA expression of NR2B and GluR2in rats’brain respectively with western blot (WB) and real-time fluorescent quantitative polymerase chain reaction (qPCR). Results1.1-BP sub-acute inhalation model(1) The actual concentrations of1-BP exposure were as below:①Low concentration group (Low group):1285.00(1198.50,1429.50) mg/m3;②Medium concentration group (Medium group):2554.00(2423.25,2735.25) mg/m3;③High concentration group (High group):5270.00(4994.00,5408.00) mg/m3.(2) Performances and behaviors of the rats:After exposed to1-BP for1week, the rats in the medium group and the high group became loss of appetite and activities. Hindlimb muscle strength of the rats decreased significantly and the hair became dirty after3weeks’exposure to1-BP in the high group. These abnormal signs also existed in the low group, but the symptoms occured latter and slighter than those of the medium group and the high group. The rats in the control group were normal all the time. There were no deaths during the experiment in all groups.(3) The order of the weight gain was:control group> low group>medium group> high group.①Medium group:The weights of rats were lower than that of the rats in the control group on day6, day9and day18to the end (P<0.05or P<0.01). On day29, the weights of rats were also lower than those of the rats in the low group (P<0.05).②High group:The weights of rats were lower than those of the rats in the control group (P<0.01) and the low group (P<0.01) on day6. And the weights of rats were lower than those of the other3groups from day9to the end(P<0.01). 2. The distribution of NR2B and GluR2in rats’brain when sub-acute inhalation of1-BPThe results of the immunofluorescence displayed that NR2B and GluR2expressed in cerebral cortex among all31-BP exposure groups and there were no significant different expression locations compared to the control group. NR2B and GluR2were nearly expressed at the same places.3. Impacts of the protein expressions of NR2B and GluR2in rats’brain induced by1-BP sub-acute inhalation(1) The protein expressions of brain’s NR2B in the medium group and the high group were all higher than those of the control group (P<0.05), but there were no significant differences between the control group and the low group (P>0.05).(2) The protein expressions of brain’s GluR2in the medium group and the high group were all higher than those of the control group (P<0.05and P<0.05), there were no significant differences between the control group and the low group (P>0.05).4. Impacts of the mRNA expressions of NR2B and GluR2in rats’brain induced by1-BP sub-acute inhalation(1) There were no significant differences of mRNA expressions of NR2B in the brain among1-BP exposure groups and the control group (P>0.05);(2) There were also no significant differences of mRNA expressions of GluR2in the brain among1-BP exposure groups and the control group (P>0.05).Conclusion1. There were expressions of NR2B and GluR2in rats’cerebral cortex among1-BP exposerue groups under conditons of this experiment, and NR2B and GluR2were expressed at nearly the same places. 2. The protein expressions of NR2B and GluR2in rats’brain increased after sub-acute inhalation of1-BP at certain concentrations, but there were no significant differences of the related mRNA. |
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