Heat-inactivated Bifidobacterium adolescentis LA20 alleviates doxorubicin-induced senescence and barrier dysfunction in feline intestinal epithelial cells

Objective To investigate the protective effects and molecular mechanisms of heat-inactivated Bifidobacterium adolescentis LA-20 (HT-LA20) against doxorubicin (DOX)-induced senescent injury in feline intestinal epithelial cells (FIECs). Methods This in vitro experimental study was conducted from November 1, 2025, through August 31, 2026, and involved only FIECs. No clinical patients or animals were included. The DOX-induced injury and senescence model was established in FIECs. The effects of HT-LA20 on cellular senescence and related proteins were evaluated by senescence-associated β-galactosidase staining, cell viability assays, and ELISA. Transcriptomic sequencing and untargeted metabolomics were integrated to elucidate the molecular regulatory mechanisms. Results Cell-based assays and transcriptomic and untargeted metabolomic analyses were performed with 4 independent biological replicates/group. HT-LA20 reversed DOX-induced reductions in cell viability and cellular senescence; upregulated tight junction proteins and mucins 1 and 2; suppressed release of IL-1β, tumor necrosis factor–α, IL-8, monocyte chemoattractant protein 1, and matrix metalloproteinase 1; and promoted VEGF and basic fibroblast growth factor (bFGF) secretion. Transcriptomic and metabolomic analyses showed that HT-LA20 reversed DOX-induced omic disturbances. Integrated multiomics Kyoto Encyclopedia of Genes and Genomes enrichment analysis indicated that its effects centered on the retinol metabolism–serotonergic synapse–intestinal immunoglobulin A immune network multitarget axis and regulation of inflammatory pathways, including nuclear factor κ B and Toll-like receptor signaling. Conclusions HT-LA20 effectively alleviates DOX-induced injury in FIECs by restoring intestinal epithelial barrier function and suppressing inflammatory senescence. Clinical Relevance These findings provide a theoretical basis for subsequent in vivo studies on postbiotics for chemotherapy-induced intestinal injury in veterinary medicine; clinical application requires further validation.