Integrated probiotic benefits of Limosilactobacillus fermentum PY-1 from the traditional fermented food “Suancai” drive antioxidant enhancement, immune protection, and gut microbiota regulation to attenuate autism-like behaviors in rats

Abstract

Autism spectrum disorder (ASD) is a neurodevelopmental condition frequently associated with elevated gastrointestinal oxidative stress. Although probiotics can mitigate oxidative stress in the gut microbiota, their specific antioxidant mechanisms in ASD remain unclear. In this study, rats were administered Limosilactobacillus fermentum PY-1, a bacterial strain isolated from traditional fermented foods and characterized by robust antioxidant activity, for one month to achieve gut colonization. Results showed that this intervention significantly ameliorated autism-like behaviors including social interaction deficits and repetitive actions, while concurrently reducing oxidative stress markers and inflammation, and enhancing intestinal barrier integrity. Histopathological analysis further revealed that liver damage was also attenuated. Notably, the treatment induced a marked reshaping of the composition of gut microbiota, characterized by the enrichment of beneficial taxa including Adlercreutzia, Christensenellaceae, Turicibacter, and Ruminococcus, while suppressing pathogenic bacteria like Erysipelatoclostridium. Metabolomic profiling validated the upregulation of indole-3-acetate, a metabolite with neuroprotective properties, alongside reduced levels of compounds linked to cognitive impairment, specifically asymmetric dimethylarginine and homogentisic acid. These findings underscore the therapeutic potential of Limosilactobacillus fermentum PY-1 in modulating gut–brain axis dynamics for reducing oxidative stress, and offer a novel strategy for ASD intervention.