Next-generation non-animal models for inflammatory bowel disease: In vitro and in silico approaches for mechanistic understanding.

Inflammatory bowel disease (IBD), encompassing ulcerative colitis and Crohn's disease, is a chronic and relapsing inflammatory condition of the gastrointestinal tract resulting from a complex interplay of oxidative stress, immune dysregulation, microbial imbalance, and epithelial dysfunction. While animal models have primarily contributed to our understanding of IBD pathogenesis, their limited translational relevance and ethical concerns have led to the accelerated adoption of New Approach Methodologies (NAMs). This review highlights the increasing importance of in vitro platforms, including intestinal epithelial cell lines, 3D organoids, and microfluidic gut-on-chip models, which offer physiologically relevant and ethically sustainable solutions. In silico strategies, such as molecular docking, network pharmacology, toxicogenomics, artificial intelligence, and machine learning, enhance these models by enabling predictive simulations of drug interactions and molecular targets. Emerging mechanisms, such as barrier modulation and multi-targeted inflammatory regulation, are being explored using NAMs. Despite significant progress, challenges remain in standardization, integrating the immune and microbiome systems, and achieving regulatory acceptance. The combination of NAMs, multi-omics, and real-world data represents a promising avenue for mechanistic research, therapeutic screening, and precision medicine in IBD.