Study on Apoptosis of Neurons in Rat Hippocampus and Expression of Related Proteins in Path of Mitochondrion after Injection of Aβ_(1-42)

Objective:To study the neuron apoptosis and the changes of the proteins related to mitochondrial pathways of apopto- sis expression in hippocampus of Alzheimer disease(AD)model rats and discuss these results' significance in the pathogenesy and pathology of AD.Methods:36 SD rats were divided into normal group,saline group and model group.The AD model rats were estab- lished by injectionβ-amyloid 1-42(Aβ_(1-42))into hippocampus.Learning and memory ability was estimated with Y maze at different time. The apoptotic neurons were detected by TUNEL method.Cytochrome C and caspase-9 protein expression in hippocampus were detected by Western-blot.Results:The frequency of attempting learning and memory of rats in model group was increased more than the rats in normal group and saline group significantly(P0.05)at the 14th day after injection.And at the 21st and 28th day after injection,the dif- ference was more remarkably(P0.01).The apoptotic neurons in hippocampus of the rats in model group were increased more signifi- cantly than that in normal group and saline group(P0.01).The expressions ofcytochrome C and caspase-9 in hippocampus of the rats in model group were increased significantly compared with normal group and saline group(P0.05).Conclusions:Aβ_(1-42)injection in hippocampus of the rats can induce the apoptosis of hippocampal neurons through activating mitochondrial pathways of apoptosis and re- sult in the impairment of the learning and memory ability of rats.And it plays an important role in the pathogenesy and pathology of AD.