补肾填髓方通过PI3K信号通路调节阿尔茨海默病模型中的突触损伤OA

Objective To explore the therapeutic effect and mechanism of Bushen Tiansui Decoction(补肾填髓方,BSTSD)and its active component icariin on Alzheimer's disease(AD). Methods(i)Animal experiments.This study conducted experiments using specific pathogen-free(SPF)grade male C57BL/6J wild-type(WT)mice and APP/PS1 double transgenic mice.The animals were divided into three groups:WT group(WT mice,n=5,receiving distilled wa-ter daily),APP/PS1 group(APP/PS1 double transgenic mice,n=5,receiving distilled water daily),and BSTSD group[APP/PS1 double transgenic mice,n=5,treated with BSTSD suspen-sion at a dosage of 27 g/(kg·d)for 90 d].Cognitive function was assessed using the Morris wa-ter maze(MWM).Post-experiment,hippocampal tissues were collected for analysis of pyra-midal cell and synaptic morphology through hematoxylin-eosin(HE)staining and transmis-sion electron microscopy(TEM).(ii)Cell experiments.The HT-22 cells were divided into con-trol group(untreated),Aβ25-35 group(treated with 20 μmol/L Aβ25-35 for 24 h),icariin group(pre-treated with 20 μmol/L icariin for 60 min,followed by 20 μmol/L Aβ25-35 for an additional 24 h),and icariin+LY294002 group[treated with 20 μmol/L icariin and 20 μmol/L LY294002(an inhibitor of the phosphoinostitide 3-kinases(PI3K)signaling pathway)for 60 min,then exposed to 20 μmol/L Aβ25-35 for 24 h],and cell viability was measured.Western blot was used to detect the expression levels of synapse-associated proteins[synaptophysin(SYP)and post-synaptic density-95(PSD-95)]and PI3K signaling pathway associated proteins[phosphorylat-ed(p)-PI3K/PI3K,p-protein kinase B(Akt)/Akt,and p-mechanistic target of rapamycin(mTOR)/mTOR]. Results(i)Animal experiments.Compared with APP/PS1 group,BSTSD group showed that escape latency was significantly shortened(P<0.01)and the frequency of crossing the origi-nal platform was significantly increased(P<0.01).Morphological observation showed that pyramidal cells in the hippocampal CA1 region were arranged more regularly,nuclear stain-ing was uniform,and vacuole-like changes were reduced after BSTSD treatment.TEM showed that the length of synaptic active zone in BSTSD treatment group was increased com-pared with APP/PS1 group(P<0.01),and the width of synaptic gap was decreased(P<0.01).(ii)Cell experiments.Icariin had no obvious toxicity to HT-22 cells when the concentration was not more than 20 μmol/L(P>0.05),and alleviated the cell viability decline induced by Aβ25-35(P<0.01).Western blot results showed that compared with Aβ25-35 group,the ratios of p-PI3K/PI3K,p-Akt/Akt and p-mTOR/mTOR in icariin group were significantly increased(P<0.01),while the protein expression levels of SYP and PSD-95 were increased(P<0.01).These effects were blocked by LY294002(P<0.01). Conclusion BSTSD and icariin enhance cognitive function and synaptic integrity in AD mod-els and provide potential therapeutic strategies through activation of the PI3K/Akt/mTOR pathway.