Probiotics restore GABAergic neurons and attenuate postnatal seizures in periventricular leukomalacia

<b>Objectives:</b> Postnatal epilepsy often arises after periventricular leukomalacia (PVL) in preterm infants and resists to treatment. Its underlying mechanisms and potential preventive strategies remain unclear. Probiotics, known to alleviate microbial dysbiosis and reduce inflammation, may offer therapeutic benefits.<b>Methods:</b> PVL injure was conducted using a combination of hypoxia-ischemia and lipopolysaccharide treatment. The rats were evaluated for seizure susceptibility, neuroinflammation, GABAergic neurons, and gut microbiota composition before and after probiotic administration. The probiotic formulation included Lactobacillus rhamnosus, Lactobacillus casei, Bifidobacterium bifidum, Bifidobacterium lactis, Bifidobacterium longum and Bifidobacterium breve in galacto-oligosaccharide and Fructooligosaccharides.<b>Results:</b> PVL rats exhibited microgliosis, reduced density of premyelinating oligodendrocytes, and decreased myelin expression (all <i>P</i> < 0.05). At postnatal days 85-90, these rats showed a significantly higher frequency of electrographic seizures and longer total seizure duration (<i>P</i> < 0.05). A significant reduction in cortical GABAergic neurons, particularly somatostatin-positive interneurons, was also observed in PVL rats compared to controls (<i>P</i> < 0.01). Treatment with probiotics restored GABAergic neurons and significantly reduced seizure frequency and duration (<i>P</i> < 0.05). Additionally, probiotics modulated gut microbiota composition and increased levels of butyric acid in both fecal samples and cerebrospinal fluid (CSF) (<i>P</i> < 0.05). Probiotic treatment also reduced cortical microglial activation and lowered CSF levels of the proinflammatory cytokine TNF-α.<b>Conclusion:</b> Probiotic supplementation may reduce seizure activity following PVL brain injury by mitigating neuroinflammation and restoring GABAergic neurons via the gut-brain axis. These findings suggest that probiotics could serve as a promising adjuvant therapy for preventing epilepsy after PVL.