Preventive Effect of Probiotic Leuconostoc mesenteroides H40 Against Cognitive Disorder by Anti-Inflammatory, Synaptic Plasticity Regulation, and Antioxidant Effects

Live <i>Leuconostoc mesenteroides</i> H40 has been reported to have probiotic properties; however, the effect of its live probiotic form on cognitive ability has not been reported. This study investigated modulatory effects of the probiotic <i>L. mesenteroides</i> H40 in an ICR mouse model (male) of cognitive disorders. Cognitive disorders were induced in mice by the addition of scopolamine (1 mg/kg/day) with donepezil (2 mg/kg/day) as a medicinal control. <i>L. mesenteroides</i> H40 significantly attenuated scopolamine-induced cognitive disorder in the novel object recognition and Y-maze tests in a concentration-dependent manner. <i>L. mesenteroides</i> H40 decreased amyloid β levels, but increased β-secretase levels. The mRNA expression levels of <i>inducible nitric oxide synthase</i> (<i>iNOS</i>) and <i>cyclooxygenase (COX)-2</i> significantly decreased following <i>L. mesenteroides</i> H40 treatment. Additionally, TNF-α, IL-1β, and PGE2 protein expression was decreased. Acetylcholine, acetylcholinesterase, choline acetyltransferase, brain-derived neurotrophic factor (BDNF), and cAMP response element-binding protein (CREB) levels were increased in the brain tissues. The antioxidant effects of superoxide dismutase, catalase, and glutathione peroxidase were also alleviated. We demonstrated that <i>L. mesenteroides</i> H40 exhibits neuroprotective effects through anti-inflammatory, synaptic plasticity regulation, and antioxidant effects. Thus, the probiotic <i>L. mesenteroides</i> H40 could be used as a prophylactic functional food for cognitive disorders.