Effects of icariin on hippocampal synaptophysin and postsynaptic density protein 95 expression in Aβ_(25-35)-induced Alzheimer disease rats

AIM To explore the effect of icariin( Ica) on hippocampal synaptophysin( SYN) and postsynaptic density protein 95( PSD-95) expression in Aβ25-35induced Alzheimer disease( AD) rats.METHODS The male SD rats were randomly divided into control group(n = 13),model group(n = 15) and Ica 120 mg·kg-1group(n = 15).The AD model rats were induced by injecting Aβ25-3510 μg into the right hippocampus,and Ica was given orally once daily for 1 week before modeling and 3 weeks after modeling.Morphological change in hippocampus was observed by hematoxylin-eosin(HE) staining.The neuron ultrastructure of hippocampal tissues was observed by transmission electronic microscope.SYN and PSD-95protein expression were assayed by western blot.RESULTS HE staining showed that hippocampal neurons arranged sparsely in the model group rats accompanied with a large number of neuron degeneration,the neurons were arranged neatly and the number of neuron degeneration decreased significantly with Ica treatment.Electron microscope showed that the number of neurons reduction,fuzzy structure,incomplete cell membrane,mitochondria swelling and vacuolar degeneration,chromatin aggregation,synapse numbers reduction in hippocampal CA3 area of the model group rats,which were alleviated with Ica treatment.The results of Western blot showed that SYN and PSD-95 protein expression decreased significantly in the model group when compared with the control group(P 0.05),which were increased with Ica treatment.CONCLUSION Ica may improve the space learning and memory ability in Aβ25-35induced AD rats by increasing the expression of synaptic marker proteins SYN and PSD-95 in rats' hippocampus.