Investigation of the Effects of Postbiotics Obtained from Pediococcus acidilactici on Specific Biomarker Expressions in Intestinal Tissue.

The intestinal mucosal barrier is a layered structure comprising fundamental components that play important roles in regulating paracellular permeability. Disruption of intestinal barrier homeostasis predisposes to infections, mucosal damage, and metabolic and allergic diseases. To provide protection against potential damage to the intestinal mucosa, agents such as prebiotics and probiotics are recommended due to their ability to secrete components and metabolites (e.g., bacteriocins, organic acids, enzymes) that can exert beneficial biological effects. The aim of this study is to comprehensively investigate the effects of a postbiotic derived from Pediococcus acidilactici on healthy rat intestinal tissue. A total of 78 Wistar Albino rats were used in this study. Following compositional analysis of the postbiotic, the animals were administered the postbiotic orally via gavage for different durations (7, 14, 21, 28 days) and at different doses (250 mg/Kg, 500 mg/Kg, 1000 mg/Kg). Characterization of the produced postbiotic revealed a diverse spectrum of biologically active compounds, including organic acids, phenolics, and volatile compounds. Histopathological examination of intestinal sections (duodenum, jejunum, ileum, cecum, colon, and rectum) showed no pathological lesions in any of the experimental groups. Conversely, immunohistochemical analysis revealed that the postbiotic increased the expression of CLDN3, OCLN, ZO1, AQP4, and AQP8, proteins involved in intestinal permeability and fluid transport, in a dose-dependent manner. These results highlight the potential of Pediococcus acidilactici as a supportive agent in a range of intestinal pathologies, including major intestinal diseases such as Crohn's disease, ulcerative colitis, and inflammatory bowel disease (IBD).