| PrefaceDonepezil Hydrochloride(DN) as an acetylcholinesterase inhibitor is widely used in the treatment of Alzheimer's disease(AD).In recent,some research found that it had some neuroprotective effect in AD.However,it's mechanism remains unknow, especially whether it can exert neuroprotective effect by regulating the expression of brain-derived neurotrophic factor(BDNF) in AD.After AD model in the rats were established,we further examined the protein expression levels of BDNF in rat hippocampus following 4 weeks administration of DN(1.5mg/kg,i.p.),by using immunohistochemistry and Western blotting.At last,we observe the effect of DN on the expression of BDNF in hippocampus in AD rats,explore the protective mechanism.Materials and Methods1.Experimental animal grouping:48 male Wistar rats weighing 200g±20g were provided by Animal Experimental Center of China Medical University.The rats were randomized into control group,AD group and treatment group,with 16 in each.2.The rat-model was established by injecting Aβ25-35 into the intracerebroventricular in the rats.DN(1.5mg/kg/d,i.p.)was given to the rats in the treatment group after the establishment of AD model,lasting 4 weeks.The others were treated with same dose isotonic Na chloride.3.Morris water maze,Silver staining and Congored coloration was done in order to assessment of AD model.4.Immunohistochemical staining for BDNF was performed. 5.Western blotting for BDNF was performed.6.Image collection analysis system was applied.The data were expressed as Mean±SD and were analyzed by SPSS 11.5 statistical package.The differences among group were compared with one-way analysis of variance.p<0.05 was regarded as the significant difference and p<0.01 was regarded as the extremely significant difference.Results1.Results of Morris water maze:with the development of experiment,escape latency in model group were prolonged compared with control group(p<0.05).2.Results of Congored coloration:orange amylaeeous aggradation in cortical and hippocampal neuron of the rats in model group were seen.However,these changes were not seen in control group.Results of silver staining:the nerve fibril derangement, twist,aggregation,and neurofibrillary tangles in cortical and hippocampal neuron of the rats in model group were seen.However,these changes were not seen in control group.3.Results of immunohistochemistry:The positive reaction product of BDNF was stained buffy.Compared with control group,the integrated optical density(IOD) of BDNF positive reaction product in model group was decresaed(p<0.05).The IOD of BDNF positive reaction product in the CA1,DG area of treat group was increase compared with model group(p<0.05).4.Results of western blotting:Compared with control group,the expression of BDNF in hippocampus of the rats in model group was decreased(p<0.01).The expression of BDNF in hippocampus of the rats in treat group showed increase tendency compared to model group(p<0.05).Conclusions1.The learning dysmnesy and pathology characteristic of AD could be simulated finely by injecting Aβ25-35 into the intracerebroventricular in rats.It may be a relatively ideal AD animal model.2.The expression of BDNF in hippocampus of AD model rats shows up-regulation,the expression of BDNF in hippocampus of the rats in DN treated group was increased compared with model group.3.Neuroprotective effect of DN was possibly due to up-regulation of BDNF in AD. |
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