Modulation of brain aging in mice: neuroprotective effects of the probiotic Lacticaseibacillus casei

The gut–brain axis plays a critical role in maintaining cognitive function and neural homeostasis, and age-related dysbiosis has been associated with neurodegenerative processes. In this study, we evaluated the neuroprotective potential of the experimental Lacticaseibacillus casei strain IMV B 7280 in young and aged mice. The animals received cyclic oral administration of the probiotic, and their cognitive performance was assessed via "open field" and "novel object recognition" tests. Neuronal and glial morphology were examined via Nissl staining and immunofluorescence for NeuN and GFAP. Compared with age-matched control mice, probiotic-treated aged mice exhibited improved locomotor and exploratory activity and increased time spent exploring novel objects. Histological and immunofluorescence analyses revealed preserved neuronal density, reduced cell condensation, and attenuation of astroglial activation in the cortical and hippocampal regions. Young mice maintained baseline neuronal and glial morphology with treatment. These results suggest that L. casei IMV B 7280 attenuates age-related neurodegenerative changes and cognitive decline. Neuroprotection is likely mediated by the modulation of the gut‒brain axis, including product metabolites, anti-inflammatory effects, and the regulation of neurotrophic and neurotransmitter pathways. Our results support the use of targeted probiotic interventions as promising strategies to promote healthy brain aging.