Effects Of Lycium Barbarum Polysaccharides On A?42-induced Oxidative Damage In SH-SY5Y Cells And Lipopolysaccharide-Induced Inflammatory Response In BV-2 Cells

Alzheimer's Disease(AD)seriously jeopardizes the physical and mental health and quality of the elderly life,has become a public health issue of great concern throughout the world.However,the pathogenesis of AD is complicated and there is no effective drug treatment at present.Therefore,it is urgent to study effective methods for preventing AD.The data show that natural products with antioxidant,anti-inflammatory and neuroprotective components play an important role in interfering with AD and other neurodegenerative diseases.Lycium Barbarum is a valuable Chinese herbal medicine with homologous medicine and food in our country.As the main active component of Lycium Barbarum,Lycium Barbarum polysaccharide has been attracting attention in the research of central nervous system diseases because of its antioxidation,immune regulation,anti-aging and neuroprotection effects.The study investigated whether Lycium Barbarum polysaccharides have a preventive effect on AD from oxidative injury and inflammation pathways.A?42-induced neuroblastoma cells SH-SY5Y oxidative damage AD model was established to investigate the effect of Lycium Barbarum polysaccharides pretreatment on A?42-induced oxidative damage in SH-SY5Y Cells.The cell viability of each group was measured by MTT assay,and the cytotoxicity of each group was measured by LDH assay.THT fluorescent staining was used to detect the effect of Lycium Barbarum polysaccharides on the aggregation and disaggregation of A?42 in vitro.Kit colorimetric assay was used to detect the levels of ROS,SOD,CAT,GSH,GSSG and MDA.Western blot was used to detect the expression of Nrf2,PI3K/Akt and NF?B signaling pathway related proteins.The results showed that Lycium Barbarum polysaccharides pretreatment can reduce A?42-induced SH-SY5Y cytotoxicity,inhibit the accumulation of A?42 and promote the depolymerization of A?42 fibers in vitro.Lycium Barbarum polysaccharides pretreatment can attenuate A?42-induced production of ROS and oxidative stress in SH-SY5Y cells;increase the expression of Nrf2,HO-1,phospho-PI3K,and Akt,and decrease the expression of phosphorylated p65,indicating that Lycium Barbarum polysaccharides can prevent A?42-induced oxidative damage in SH-SY5Y cells,and its mechanism was related to the activation of PI3K/Akt/Nrf2 signaling pathway to reduce A?42-induced ROS and oxidative stress in SH-SY5Y cells.LPS-induced BV-2 microglial inflammation AD model was established to investigate the effect of Lycium Barbarum polysaccharides pretreatment on LPS-induced BV-2 microglial inflammatory response.The cell viability of each group was measured by MTT assay.NO and iNOS were detected by kit colorimetric assay.The levels of inflammatory cytokines TNF-a,IL-6 and IL-1? were determined by ELISA.The expression of NF-?B signaling pathway related proteins was detected by Western blot.The results showed that Lycium barbarum polysaccharide pretreatment can reduce NO production,decrease iNOS activity,decrease the levels of inflammatory cytokines TNF-a,IL-1? and IL-6,down-regulate the expression of COX-2 protein,and decrease the phosphorylation of p65 and IKKa expression,indicating that Lycium barbarum polysaccharides can attenuate the production and release of inflammatory cytokines in LPS-stimulated BV-2 microglial,and its mechanism was related to the inhibition of the activation of NF-?B signaling pathway.The above results suggest that Lycium Barbarum polysaccharide can play a role in preventing ADneuroprotection by relieving oxidative damage and inflammatory response,and provides a scientificbasis for Lycium Barbarum to prevent AD and other neurodegenerative diseases.