Study On The Therapeutic Effect And Possible Mechanism Of Rhizoma Drynariae On Learning And Memory Impairment In AD Ovariectomized Rats

Objective The aim of this study is to explore the therapeutic effects of Rhizoma Drynariae decoction on learning and memory dysfunction in AD rats induced by castration and its possible mechanism by means of animal behavioral,morphological and biochemical experiments.Methods Sixty female SD rats were randomly divided into sham-operation group,model group,traditional Chinese Medicine Group(Drynaria low,middle and high dose group),Estradiol valerate group,except sham-operation group,the animal model of AD was established by bilateral ovariectomy,the Sham Operation Group and the model group were given double distilled water,the Chinese medicine group were given the corresponding concentration of Rhizoma drynariae decoction,and the positive control group were given the corresponding dosage of Estradiol valerate suspension.Filling the stomach8 weeks,the water maze training and test were performed at the eighth week,and the perfusion and brain tissue were obtained.The morphological and quantitative changes of Nissl bodies in CA1 and CA3 regions of the rat hippocampus were detected by Nissl staining and the neuron injury was observed preliminarily.The morphology,complexity and density of dendritic spines in hippocampus were observed by Golgi’s method staining.The expression of Estrogen receptor(ERβ),apoptosis(caspase 3),synaptophysin protein(NMDAR-2B)and related protein(GSK-3β、ERK1/2)in hippocampus of rats were detected by Western blotting.Results 1.The results of water maze test showed that compared with the model group Drynaria decoction could shorten the time of crossing the platform,shorten the escape latency and increase the times of finding the platform in ovariectomized AD rats.(P<0.05)2.The results of Nissl staining showed that compared with the model group Drynaria decoction could increase the number of Nissl bodies in CA1 and CA3 regions of hippocampus in castrated AD rats.(P<0.05)3.Results from Golgi’s method showed that compared with the model group Drynaria decoction could increase the complexity and density of dendritic spines in hippocampus of ovariectomized AD rats.4.Compared with the model group,the expression of ERβwas significantly increased in the Drynaria high dose group;low,middle,high-dose group and positive group expression of Synaptophysin protein NMDAR-2B was promoted by Rhizoma Drynariae decoction(P<0.05);low,middle,high-dose group and positive group expression of GSK-3β activity was inhibited,and the expression of Caspase 3 was significantly decreased in the Drynaria middle dose group(P<0.05).Conclusions Drynaria may increase the expression of ERβ,decrease the expression of GSK-3β and Caspase-3,and up-regulate the expression of NMDAR-2B in the hippocampus of AD model rats,thus improving the injury of neurons,finally,the cognitive dysfunction of AD model rats induced by castration was reversed.