Effect of pH and lipopolysaccharide on tight junction regulators and inflammatory markers in intestinal cells as an experimental model of weaning transition in dairy calves

Acidic conditions combined with the presence of lipopolysaccharide (LPS) may increase permeability gastrointestinal epithelium. Feeding starch-rich starter to dairy calves is associated ruminal acidosis and decreases pH other segments tract, that affects tight junction regulator. The objective was evaluate effect combination different (7.4 vs. 6.0) LPS concentrations (0, 0.5, 10 ng/mL) in intestinal cells on regulators, inflammatory markers, permeability. human colon carcinoma Caco-2 cell line used main treatment a 2 × 3 factorial arrangement. acidic (pH or physiologic 7.4), whereas 0, ng/mL. After reached 70%–80% confluence, media were replaced each respective medium. Cells treated for h mRNA abundance analysis, 6 protein determination, 3, 6, 12, 24 determination. Protein myosin light-chain kinase (MYLK) toll-like receptor 4 (TLR4) measured by western blot. IL-8, MYLK, peroxisome proliferator activated gamma, nuclear factor kappa B (Nfkb1) determined real-time, quantitative PCR. Paracellular Lucifer yellow after 21 d incubation. Cell culture performed biological triplicate; replicate PCR had technical replicates, assay one replicate. MIXED procedure SAS (SAS Institute Inc.) LPS, pH, as fixed effects. Significance declared at P ≤ 0.05 tendencies when < 0.10. Increasing doses did not affect MYLK TLR4, nor PPRG. tended IL-8 while interactively increased Nfkb1, where Nfkb1 lower exposed 6.0 0 ng/mL LPS. Contrary expectations, cells. greater versus 7.4. Also, TLR4 than 7.4, it decreased exposure h. In addition, Permeability 7.4 treatment. summary, its interaction showed less impact expected dependent variables measured, which might be attributed adopted clinically achievable likely being high enough draw strong response observed literature. On hand, far more relevant, modulating vitro models.