Alleviating the Effect of Branched-Chain Fatty Acids on the Lipopolysaccharide-Induced Inflammatory Response in Calf Small Intestinal Epithelial Cells

This study examined branched-chain fatty acids (BCFAs)' effects on oxidative stress, energy metabolism, inflammation, tight junction disruption, apoptosis, and Toll-like receptor 4/nuclear factor kappa-B (<i>TLR4/NF-κB</i>) signaling in lipopolysaccharide (LPS)-induced calf small intestinal epithelial cells (CSIECs). Eight groups were used: a control group, an LPS-induced group, and six BCFA treatment groups (12-methyltridecanoic acid (iso-C14:0), 13-methyltetradecanoic acid (iso-C15:0), 14-methylpentadecanoic acid (iso-C16:0), 15-methylhexadecanoic acid (iso-C17:0), 12-methyltetradecanoic acid (anteiso-C15:0), and 14-methylhexadecanoic acid (anteiso-C17:0)) with LPS. The BCFA pretreatments significantly increased CSIEC activity compared to the LPS-induced group, with iso-C14:0 showing the highest activity (89.73%). BCFA reduced Reactive Oxygen Species (ROS) generation and malondialdehyde (MDA) levels and improved the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities and glutathione (GSH) levels. Iso-C16:0 optimized total antioxidant capacity (T-AOC). BCFA enhanced the mitochondrial membrane potential, Adenosine Triphosphate (ATP) enzyme activity, and ATP content, with iso-C14:0 increasing ATP by 27.01%. BCFA downregulated interleukin (<i>IL</i>)<i>-1β</i>, <i>IL-8</i>, tumor necrosis factor (<i>TNF</i>)-<i>α</i>, and interferon (<i>INF</i>)-<i>γ</i> gene expression, reduced IL-6 levels, and increased <i>IL-10</i> expression. Myeloid differentiation factor 88 (<i>MyD88</i>) mRNA levels were reduced. BCFA alleviated Zonula Occludin (<i>ZO-1</i>), <i>Claudin-1</i>, and <i>Claudin-4</i> decrease and increased Occludin levels. BCFA mitigated LPS-induced increases in <i>Caspase-3</i> and BCL2-Associated X (<i>BAX</i>) mRNA levels, reduced <i>Caspase-8</i> and <i>Caspase-9</i> expression, and increased B-Cell Lymphoma-2 (<i>BCL-2</i>) mRNA levels. The Entropy Weight-TOPSIS method was adopted, and it was discovered that iso-C15:0 has the best effect. In summary, BCFA supplementation mitigated oxidative stress and enhanced mitochondrial function. BCFA inhibited <i>TLR4/NF-κB</i> signaling pathway overactivation, regulated inflammatory cytokine gene expression, reduced cellular apoptosis, preserved tight junction integrity, and supported barrier function.