| Parkinson’s disease(PD)is a complex neurodegenerative disease caused by multiple factors.To date,there is no treatment that can prevent or cure PD.Nevertheless,the development of treatments to prevent and cure PD remains a top priority,and with the development of gut flora,there is growing evidence that PD is likely to begin in the gut and spread to the brain.Therefore,gut flora is a potential target for the alleviation and treatment of PD.Bifidobacterium,as a probiotic and core genus of intestinal bacteria,is essential for maintaining intestinal health and homeostasis,and an in-depth investigation of the mitigating effects of Bifidobacterium on PD is of great market value.The mechanism of “microbiota-gut-brain axis” to regulate the development of neurodegenerative diseases such as PD has been a hot research issue,and provides a theoretical basis for the development of dietary supplements targeting intestinal flora to alleviate PD Based on the above research background,this paper firstly obtained Bifidobacterium breve CCFM1067 with neuroprotective potential through in vitro cellular experiments;then investigated the mechanism of B.breve CCFM1067 alleviating PD in mice through in vivo animal experiments;Finally,animal experiments were conducted to evaluate the alleviative effect of the intervention of prebiotic with neuroprotective compounded with B.breve CCFM1067 effect on PD.The main findings were as follows:A total of 60 strains of six Bifidobacterium species were used to establish an in vitro neuroinflammatory cell model using LPS-induced BV2 microglia.By measuring the effects of60 strains of Bifidobacterium on the production of NO in the supernatant of LPS-induced BV2 cells,we initially obtained six strains of Bifidobacterium that could significantly inhibit the production of NO in the supernatant of LPS-induced BV2 cells,namely D1,D3,C5,C7,A2 and Y1;further,the effects of the above six strains of Bifidobacterium on the expression levels of genes of the anti-oxidative stress pathway and the expression levels of cellular inflammatory factors in BV2 cells after LPS stimulation were determined.It was found that B.breve D3 had a better ability to inhibit LPS-induced oxidative stress and inflammatory response in BV2 cells,and had a potential neuroprotective effect.Therefore,subsequent experiments were conducted using B.breve D3(CCFM1067)as the main study strain.A mouse model of PD was established based on 1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine(MPTP)induction,and the alleviating effects of B.breve CCFM1067 intervention on Parkinson’s disease mice were investigated in vivo.The results showed that B.breve CCFM1067 intervention could significantly alleviate the motor dysfunction of Parkinson’s disease mice,including the motor agility,balance and coordination of the mice;at the same time,it could alleviate the neuropathological changes,inhibit the neuroglial response,increase the content of neurotrophic factors and enhance the level of striatal neurotransmitters in PD mice,and achieve neuroprotective effects;further studies showed that B.breve CCFM1067 also had the ability to inhibit oxidative stress,alleviate neuroinflammation and colonic inflammation in PD mice,and reduce damage to the blood-brain and intestinal barriers.The mechanism of PD alleviation by B.breve CCFM1067 was investigated from three perspectives: fecal short-chain fatty acids,intestinal flora and fecal metabolites.The results showed that B.breve CCFM1067 intervention could significantly increase the content of fecal short-chain fatty acids,mainly including acetic acid,butyric acid,isobutyric acid and isovaleric acid,in MPTP-induced Parkinson’s disease mice.The results of flora analysis showed that B.breve CCFM1067 intervention could alleviate the decrease of microbial community richness and abnormal changes of intestinal microbial composition in PD mice,reduce the abundance of MPTP-induced intestinal pathogenic Escherichia-Shigella in PD mice,increase the beneficial bacteria Bifidobacterium and Akkermansia to alleviate oxidative stress and inflammation in the pathogenesis of PD.Fecal metabolomic analysis showed that the relative levels of the fecal metabolites indole-3-acrylic acid increased 14.96-fold,decanoic acid increased 1.95-fold and N-acetylhistamine decreased 4.95-fold in PD mice after B.breve CCFM1067 intervention,and the purine metabolism,taurine and subtaurine metabolism and arginine biosynthesis-related pathways involved in the differential metabolites were significantly enriched.Finally,the alleviating effects of different synbiotic combinations on PD mice were evaluated based on the MPTP-induced PD mouse model.The results showed that the Fucoidan+ CCFM1067 synbiotic intervention group showed better effects than CCFM1067 intake alone in alleviating motor dysfunction,ameliorating pathological changes in Parkinson’s disease mice,inhibiting glial reactivity,increasing striatal neurotransmitter levels and reducing the levels of reactive oxygen species in the midbrain;In contrast,the FOS + CCFM1067 synbiotic intervention group was more effective in increasing brain-derived neurotrophic factor levels and alleviating neuroinflammation and colonic inflammation;the GOS + CCFM1067 synbiotic intervention group did not stand out in all indices.Non-targeted metabolomic analysis showed that the intervention in the Fucoidan + CCFM1067 group resulted in significant enrichment of the biosynthetic metabolic pathways of “Aminoacyl-t RNA biosynthesis”,and “Phenylalanine,tyrosine and tryptophan biosynthesis”.The intervention in the group of Fucoidan + CCFM1067 increased the relative content of the fecal differential metabolite phenylalanine by 3.10-fold and the relative content of tyrosine by 3.16-fold.Phenylalanine and tyrosine are potential markers for their role in alleviating PD. |
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