以阿茲海默症模式小鼠分析潛力精神益生菌對腸道菌相與海馬迴基因網絡之影響

Alzheimer’s disease (AD) is the most common form of dementia that affects memory, thinking, and behaviors. Studies have proved that there is a bidirectional communication between the gut and the brain, known as the gut-brain axis. Studies have shown that probiotics are believed to help improving enteric microflora and affect the brain through the gut-brain axis. Recently, there has been increasing evidence indicate the association between gut dysbiosis and AD, but the role of gut microbiota in AD pathogenesis remains elusive. Lacticaseibacillus paracasei PS23 is a probiotic that was isolated from healthy human feces, and several studies suggest that PS23 can ameliorate cognitive decline, aging progression, and depression. However, the effect of PS23 on AD remains to be studied. In this study, PS23 showed a tendency of improving in short-term memory and spatial learning ability in behavior tests, which indicated that PS23 can improve the cognition of AD model mice. Administration of live- PS23 (L-PS23) increased synaptophysin and decreased caspase-1 in the hippocampus. Heat-killed PS23 (H-PS23) reduced protein carbonylation levels caused by reactive oxygen species. In addition, PS23 increased the abundance of microbiota related with metabolism, immune functions, and short-chain fatty acids (SCFAs) in AD mice. Also, PS23 alters genes expression of SRP54, P2Y2R, growth hormone, and prolactin in the mouse hippocampus. These results suggest that L-PS23 might decrease inflammation by increasing the production of SCFAs in AD mice, and H-PS23 increases neurogenesis might be through increasing gene expression of growth hormone and alter the abundance of microbiota in AD mice. The administration of both L-PS23 and H-PS23 may increase the memory and cognition by increasing the gene expression of prolactin. PS23 could be a potential preventative and therapeutic probiotics for AD.