• Food Science of Animal Resources
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• v.43 no.6
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• pp.1044-1054
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• 2023

Growing evidence indicates a crucial role of the gut microbiota in physiological functions. Gut-brain axis imbalance has also been associated with neuropsychiatric and neurodegenerative disorders. Studies have suggested that probiotics regulate the stress response and alleviate mood-related symptoms. In this study, we investigated the effects of the probiotic Lacticaseibacillus rhamnosus IDCC3201 (L3201) on the behavioral response and fecal metabolite content in an unpredictable chronic mild stress (UCMS) mouse model. Our study shows that chronic stress in mice for three weeks resulted in significant changes in behavior, including lower locomotor activity, higher levels of anxiety, and depressive-like symptoms, compared to the control group. Metabolomic analysis demonstrated that disrupted fecal metabolites associated with aminoacyl-tRNA biosynthesis and valine, leucine, and isoleucine biosynthesis by UCMS were restored with the administration of L3201. Oral administration of the L3201 ameliorated the observed changes and improved the behavioral alterations along with fecal metabolites, suggesting that probiotics play a neuroprotective role.

• Food Science of Animal Resources
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• v.43 no.4
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• pp.612-624
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• 2023

The gut-brain axis encompasses a bidirectional communication pathway between the gastrointestinal microbiota and the central nervous system. There is some evidence to suggest that probiotics may have a positive effect on cognitive function, but more research is needed before any definitive conclusions can be drawn. Inflammation-induced by lipopolysaccharide (LPS) may affect cognitive function. To confirm the effect of probiotics on oxidative stress induced by LPS, the relative expression of antioxidant factors was confirmed, and it was revealed that the administration of probiotics had a positive effect on the expression of antioxidant-related factors. After oral administration of probiotics to mice, an intentional inflammatory response was induced through LPS i.p., and the effect on cognition was confirmed by the Morris water maze test, nitric oxide (NO) assay, and interleukin (IL)-1β enzyme-linked immunosorbent assay performed. Experimental results, levels of NO and IL-1β in the blood of LPS i.p. mice were significantly decreased, and cognitive evaluation using the Morris water maze test showed significant values in the latency and target quadrant percentages in the group that received probiotics. This proves that intake of these probiotics improves cognitive impairment and memory loss through anti-inflammatory and antioxidant mechanisms.

• Journal of Dairy Science and Biotechnology
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• v.39 no.3
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• pp.94-103
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• 2021

The lack of an effective treatment for Alzheimer's disease (AD) stems primarily from incomplete understanding of AD's causes. A rapidly growing number of scientific reports highlight important roles played by peripheral infections and intestinal bacterial flora in pathological and physiological functions involving the microbiome-intestine-brain axis. The microbiome controls basic aspects of the central nervous system (CNS), immunity, and behavior, in health and disease. Changes in the density and composition of the microbiome have been linked to disorders of the immune, endocrine, and nervous systems, including mood changes, depression, increased susceptibility to stressors, and autistic behaviors. There is no doubt that in patients with AD, restoration of the intestinal microbiome to a composition reminiscent of that found in healthy adult humans will significantly slow the progression of neurodegeneration, by ameliorating inflammatory reactions and/or amyloidogenesis. In the near future, better understanding of bidirectional communication between the brain and microbiota will allow the development of functional diets using specific probiotic bacteria.