Restoration of intestinal barrier integrity in environmental ASD models by food-borne Lactiplantibacillus plantarum strains

Rationale: Autism Spectrum Disorder (ASD) is a neurodevelopmental condition characterized by social communication deficits and gastrointestinal (GI) symptoms. This study evaluated intestinal barrier integrity in murine ASD models induced by immune activation at different developmental stages and assessed whether supplementation with two Lactiplantibacillus (Lpb.) plantarum strains could modulate these alterations. Methods: Three environmental murine models were generated: Maternal Immune Activation (MIA), elicited by poly I:C administration at gestational day 12.5; Postnatal Immune Activation (PIA), triggered by LPS injection at postnatal day (PND) 9; and Early Immune Activation (EIA), obtained by combining both treatments. Lpb. plantarum was administered to dams via drinking water (109 CFU/mouse/day), with offspring exposed just through lactation. At PND21, intestinal permeability and inflammatory status were assessed in 96 mice of both sexes. Colon gene expression of tight junction markers (Cldn1, Cldn3, Ocln, Tjp1) and cytokines (Il-1, Il-2, Il-6, Il-10, Il-17A, Il-23, Ifn, Ifn, Tnf, Tgf) was analyzed by RT-PCR. ZO-1 protein levels were quantified by ELISA and in vivo permeability was evaluated by FITC-dextran assay. Results: Lpb. plantarum significantly modulated tight junction gene expression, with greater upregulation in immunolesioned groups. Correlation analyses of permeability markers revealed sex-dependent differences, particularly for Cldn3. Cytokine gene expression was significantly increased in MIA and EIA groups, except for Il-1 which increased only in PIA females. Probiotic supplementation reduced the expression of most cytokines, supporting an anti-inflammatory effect. Conclusions: Maternal probiotic administration during gestation and lactation modulated intestinal permeability and inflammatory responses in offspring, suggesting that selected L. plantarum strains represent a promising complementary strategy for ASD-related GI dysfunction. Nevertheless, comprehensive large-scale clinical trials are required to definitively ascertain therapeutic efficacy and to delineate optimal intervention protocols.