Neuroprotective effects ofand bacterial probiotics in a rotenone-induced rat model of Parkinson's disease.

Abstract

BACKGROUND: Recent evidence suggests that Parkinson's disease (PD) may originate in the gut and impact upon the central nervous system via the gutbrain axis, highlighting the significance of the gut microbiome. The aim of this study was to explore the neuroprotective potential of probiotics and their impact on CD163 expression in muscularis macrophages in a rat model of rotenone-induced PD. MATERIALS AND METHODS: Forty-eight rats were divided into six groups: control, vehicle control, PD induced by rotenone consisting of positive control (rotenone only), a yeast probiotic group (25 mg/kg Saccharomyces boulardii), a bacterial probiotic group (10⁹/cfu/day probiotics mixture), and a combined yeast-bacterial probiotic group (25 mg/kg Saccharomyces boulardii, 10⁹/cfu/day probiotics mixture). We performed motor evaluations, tyrosine hydroxylase immunohistochemistry, stereological neuron counting in the hippocampus and cerebellum, and analysed CD163 expression in muscularis macrophages via flow cytometry. The obtained data was statistically analysed. RESULTS: Rotenone-treated groups exhibited severe motor dysfunctions. Tyrosine hydroxylase immunoreactivity in the corpus striatum was lower in all rotenone- treated groups, but was higher in those with probiotic supplementation than in the positive control group. Rotenone caused degenerative changes in hippocampal pyramidal neurons, while probiotics demonstrated neuroprotective effects. CD163 expression in muscularis macrophages was significantly increased in the rotenone-treated groups compared to the control and vehicle control group. CONCLUSIONS: Our findings suggest that probiotics mitigate rotenone-induced neurodegeneration by preserving dopaminergic neurons and modulating gut-immune interactions. Determining the phenotypic characterisation of muscularis macrophages is essential, and their relationship with the microbiome may play a significant role in neurodegenerative diseases.