| Objective:The aim of this study was to investigate the effect of Pyracantha fortuneana polysaccharide(PFP)on the cognition impairment and inflammatory response in 5×FAD mice and its possible mechanism.Method:Firstly,the behavioral differences of mice at the different months(6-month and 9month)were observed by open field test,novel object recognition test,Morris water maze and gait experiment.Secondly,to further observe the effect of PFP on the pathological characteristics in brain and central and peripheral inflammation of 5×FAD mice.We observe the differences of Aβ plaque area in the cortex and hippocampus of mice in each group by Thio-s staining;The proliferation and activation of microglia and astrocytes in the cortex and hippocampus were observed by immunohistochemistry;The levels of proinflammatory cytokines and chemokines in peripheral serum and hippocampus were detected by Luminex;The changes of CD4~+T cells and their subtypes(Th1,Th2 and Th17)in peripheral serum and whole brain were observed by flow cytometry.Subsequently,we observed the effect of PFP on the gut microbiota in 5×FAD mice,and further explore the relationship between gut microbiota and inflammatory factors.At the same time,we combined with metagenomic sequencing analysis to detect the functional differences of gut microbiota,to find the key metabolites of gut microbiota flora and their changes.Finally,we observed the effect of 500 mg/kg sodium butyrate on the behavior of 5×FAD mice by the above behavioral experiments;Meanwhile,we observed the effect of sodium butyrate on the brain pathological features of 5×FAD mice included AβPlaque area and the activation of glial cell,and the effects of sodium butyrate and PFP on GRP109a/NLRP3 pathway were observed by Western blot.Result:1.PFP can improve the decrease of the learning and memory ability at different age groups(6-month and 9-month)and ameliorate the decrease of the motor ability induced by aging in 5×FAD mice.2.PFP can significantly reduce the area of Aβ plaque,the proliferation and activation of microglia and astrocytes in the Cortex and hippocampus 5×FAD mice,and the pathological characteristics of 6-month-old mice brain improved more significantly.3.The levels of IL-6,TNF-α,IFN-γ,CCL7 and CCL20 in brain and IL-1β,IL-2,IL-6,TNF-α,IFN-γ,CCL2,CCL3,CCL 4,CCL7,CCL19,CCL20,CXCL11 and CXCL12 in serum of 5×FAD mice were significantly decreased by PFP.Flow cytometry showed that PFP could reduce the percentage of CD4~+T cells and the percentage of Thl and Th17 cells in brain and peripheral.4.PFP can regulate the changes of gut microbiota in 5×FAD mice to promote the production of butyrate.5.Butyric acid and PFP can improve the impairment of learning and memory and the changes of brain neuropathology in 5×FAD mice,which may be closely related to the inhibition of NLRP3 inflammatory pathway.Conclusion:PFP may change the structure of gut microbiota,increase the abundance of butyric acid producing bacteria in intestine of 5 ×FAD mice,increase the content of butyric acid in blood,and improve the decline of learning and memory ability,Aβ deposition in brain,inflammation in central nervous system and blood of 5 ×FAD mice,and these pathological changes in brain may be related to the inhibition of the expression of NLRP3 inflammation. |
