| Objective1-bromopropane(1-bromopropane,1-BP)is a kind of volatile organic solvents,since the short half-life,almost no damage to the ozone layer,it has become the alterative of fluorine and chlorine hydrocarbon ozone depletion substances,widely used for precision instrument cleaning,also often replace potentially carcinogenic risk of dry lotion for dry cleaning industry now.As the increasing usage and production of 1-BP,exposure population gradually expanding,and the 1-BP poisoning cases has being appered in recent years.The patients intoxicated with 1-BP often first symptomed with the central nervous system(CNS)damage such as headache,dizziness,memory disorders,depression or anxiety,and followed by the damage symptoms of peripheral nerve system(PNS)such as limb numbness,loss ot lower limb vibration sense,the serious poisoning often were characterized by the ataxia,even paralysis.There were obvious differences between 1-BP intoxication and other nuurotoxic organic solvent,with more obviously and severely CNS damaged symptoms of in the human poisoning cases reported and animl treated with 1-BP..Because 1-BP the exact mechanism of neutoxicity is unclear,the specific clinical effective treatment measures is lack.Accumulating data indicated that the 1-BP neurtoxicity were related with the oxidative stress and neuroinflammation of brain.Edaravone(EDA),5-methyl-2-phenyl-1,2-dihydropyrazol-3-one,widely were used to treatement of oxidative damage myocardial ischemia reperfusion injury,due to its strong anti-inflammatory effects and scavenging free radicals.Thus,in this experiment,the nurotoxicity of 1-BP of rats was developed by the oral treatiment of1-BP at the dosage of 800mg/kg.bw,combied with EDA intervention.Then,Morris water maze test was employed to evaluate the neurotoxicity of 1-BP by the change of cognitive function in experimental animals,and folloed by the histopathological observation of brain,the detection of the activity of mitochondria complex Ⅰ-Ⅳ,the oxidative and nueroinfalmmatory status of rat brains were also carried out,try to further explain the mechanism of 1-BP neurotoxicity and find the effective intervention targets.Methods1.The animal treatment.Adult male Wistar rats were given 800 mg/kg.bw 1-BP to develop the model of the 1-BP nerotoxicity,4h later,followed by the 1 m/kg.bw,3 m/kg.bw and 5 m/kg.bw EDA treatment respectively for consecutive 12 d.2.Morris Water Maze(MWM)test.The Since the 7th day of experiment,all rats were subjected to the consecutive 5 d place navigation in MWM test to measure the escape latency and the total swimming distance.On the 6th day of MWM,spatial probe test was performed and the crossing times of rats were recorded to evaluate the spatial memory ability.3.Nissl staining(thionin):4 rats in each group were randomly selected and the frozen section of whole brain were sliced for thionin staining to abserve the change of PFC and HPC...4.Immunohistochemical staining.The neurons and lba-1 were evidenced by the immunohistochemical staining,then were counted under microscope using Image J.5.The rat brains from each group were harvested by capitation for the determination of activities of mitochondria complex Ⅰ-Ⅳ.6.The tumor necrosis factors-a(TNF-a)and nitric oxide(NO)were detected by ELISA and nitrate reductase method respectively.The reduced glutathione(GSH)and oxidized glutathione(GSSG)were also measured and followed by the calculation of GSH/GSSG ratioResults1.The results of MWM test showed that the escape latencies of rats in 1-BP group were increased by the 60.8%,81.9%,124.0%,323.3%respectively during the 2～5day of MWM,the total swimming distance by increase of 47.0%,66.4%,106.0%,277.6%compared to control rats.After co-treatment at different dosages of EDA with 1-BP,the escape latencies of rats in 1-BP+EDA 5 mg/kg.bw group were decreased by 38.4%and 44.3%(P<0.01),and the total swimming distance decreased 34.5%and 43.3%(P<0.05,P<0.01),respectively,compared with the 1-BP treated rats on the d 4 and d 5 of MWM test.In the spatial probe trial,the crossing times of rats in 1-BP group were significantly decreased,compared to the conty2.Morphologically,the thionin staining and immunohistochemistry revealed significant microglia activation and neuron loss in the rat bain of 1-BP model group,such above alterations were significantly alleviated in by the EDA treatment.3.1-BP significantly reduced the mitochondria complex activity in prefrontal cortex of rats(P<0.05,P<0.01).Co-treatment of EDA with 1-BP could significantly improve the mitochondria complex activity(P<0.05,P<0.01)with the dose-dependent manner(P<0.01).4.NO and TNF-a levels increase 147.6%and 18.7%in rats treated with 1-BP respectively compared with control values(P<0.05,P<0.01).In addition,the contents of NO and TNF-a were decreased in 1-BP+EDA 1,3 and 5 mg/kg.bw groups,with a decrease of 53.8%,55.4%and 59.8%in NO,and 12.2%,15.8%and 22.2%in TNF-a(P<0.05,P<0.01),respectivelyes.All the differences between 1-BP group and control group were significant(P<0.05,P<0.01).GSH content in prefrontal cortex of rats treated with 1-BP were significantly lower than the control values(P<0.01),while the GSSG content was significantly increased(P<0.O1)and the GSH/GSSG ratio correspondingly decreased(P<0.01).EDA reversed the decrease of GSH content and GSH/GSSG ratio,as well as the increase of GSSG content induced by 1-BP in prefrontal cortex of rats(P<0.05).Conclusion1.1-BP could induce learning and memory deficits in rats,which might be associated with neuron damage and loss in brain.2.1-BP could activate the microglia,elevat the levels of TNF-and NO.The edaravone significantly alleviate the its neurotoxicity,which might related to the inhibition of neuroinflammation resulted from 1-BP exposue.3.1-BP could damage the mitochondria and result in oxidative stress by depletion of GSH and elevation of GSH/GSSG in brain.EDA could effective protecd against the injuries of mitochondria,lessen the oxidative damages,and reduce neuron damage and losss under 1-BP exposure. |
PDF Full Text Request