Preventive Effects of Probiotic and Postbiotic <i>Lacticaseibacillus paracasei</i> HY2782 on DSS-induced Colitis in Mice: Comparable Efficacy of Live and Heat-Killed Forms

Ulcerative colitis is chronic inflammatory bowel disease characterized by intestinal inflammation and barrier dysfunction. Probiotics and postbiotics have been proposed as dietary interventions for intestinal health; however, their comparative preventive effects remain unclear. In this study, we evaluated the preventive effects of probiotic and postbiotic forms of <i>Lacticaseibacillus paracasei</i> HY2782 in a dextran sulfate sodium (DSS)-induced colitis mouse model. Male C57BL/6 mice were orally administered live or heat-killed HY2782 prior to DSS exposure. Disease activity index, colon length, histopathological damage, inflammatory cytokine expression, and intestinal barrier-related gene expression were assessed, and gut microbiota composition was analyzed using 16S rRNA gene sequencing. Both probiotic and postbiotic forms of HY2782 significantly alleviated DSS-induced colitis, as evidenced by reduced disease activity, preserved colon length, improved histological features, and suppressed expression of pro-inflammatory cytokines. In addition, HY2782 treatment restored the expression of tight junction-related genes in colonic tissue. Gut microbiota analysis revealed limited but specific compositional changes following HY2782 administration, with no marked differences between live and heat-killed forms. These findings demonstrate that both probiotic and postbiotic forms of HY2782 exert preventive effects against DSS-induced colitis with no statistically significant differences between the two preparations. This suggests that HY2782 has significant potential as a versatile functional ingredient in both live and inactivated forms for the prevention of inflammatory bowel diseases, although further studies are needed to fully elucidate their distinct mechanistic roles.