Preventive effects of GABA-producing postbiotics derived from Levilactobacillus brevis against chronic sleep deprivation-induced gut-brain axis dysfunction, neuroinflammation, and behavioral impairments in mice

Chronic sleep deprivation (CSD) is increasingly recognized as a contributor to gut dysbiosis, systemic inflammation, and neurobehavioral impairments via the gut-brain axis. γ-Aminobutyric acid (GABA)-producing postbiotics, derived from microbial fermentation, offer potential in mitigating such dysfunctions. This study investigates the effects of GABA-producing postbiotics produced by Levilactobacillus brevis on CSD-induced gut and brain disturbances in mice. Male C57BL/6 mice were subjected to 30 days of sleep fragmentation and treated with low (250 mg/kg) or high (500 mg/kg) doses of postbiotics. Behavioral tests revealed that GABA-producing postbiotics significantly alleviated anxiety- and depression-like behaviors. Postbiotic treatment restored intestinal tight junction protein expression (ZO-1, Claudin-1), increased glutathione peroxidase activity, and reduced serum lipopolysaccharide and TNF-α levels, indicating improved intestinal barrier function and attenuated systemic inflammation. Postbiotic treatment promote the growth of beneficial genera such as Ruminococcus and Akkermansia, while also elevating fecal propanoic acid concentrations. In the brain, postbiotics upregulated blood-brain barrier (BBB) associated genes and reduced neuroinflammatory gene expression. Correlation analysis highlighted microbial signatures linked to short-chain fatty acids, intestinal tight junction proteins, serum LPS and TNF-α levels, as well as hypothalamic inflammatory, BBB gene expressions and anxiety. These findings suggest that GABA-producing postbiotics ameliorate CSD-induced gut-brain axis disruption by modulating the microbiota, restoring barrier functions, and suppressing systemic and neuroinflammation. This study supports the potential application of GABA-producing postbiotics as a dietary strategy to mitigate sleep loss-related physiological and behavioral impairments.