Luteolin and Chrysin Could Prevent E. coli Lipopolysaccharide-Ochratoxin A Combination-Caused Inflammation and Oxidative Stress in In Vitro Porcine Intestinal Model.

Abstract

Simple SummaryEnvironmental stressors, such as mycotoxins and enteropathogenic bacteria, can exert a detrimental effect on the gastrointestinal tract of the swine on contaminated corn-based feed which leads to the development of retarded growth; weight loss, thus, contributes greatly to lowered meat productivity. Plant-derived compounds such as flavonoid-type chrysin and luteolin were investigated in porcine enterocytes to evaluate their beneficial properties in gut damage. Toxic effects of ochratoxin A mycotoxin and bacterial outer membrane component, lipopolysaccharide could not be alleviated by the applied flavonoids even in combinations. However, luteolin and chrysin could prevent the excessive inflammatory responses by lowering cytokines’ production elicited by mycotoxin and bacterial toxin. Due to their antioxidant properties, these flavonoids were effective in compensating redox homeostasis tipped by combined exposure of ochratoxin A and inflammatory lipopolysaccharide. The porcine intestinal epithelial cell model applied by us was proven to be suitable for studying the harmful effects of the toxins and at the same time to evaluate the protective effects of flavonoids without living animal sacrifices. This study also suggests that mycotoxin-weakened intestinal function might result in the development of enteropathogen-caused secondary infections.Ochratoxin A (OTA) and lipopolysaccharide (LPS) intake can cause gastrointestinal disorders. Polyphenolic chrysin (CHR) and luteolin (LUT) display anti-inflammatory and antioxidant properties. Porcine intestinal epithelial (jejunal) IPEC-J2 cells were treated with OTA (1 µM, 5 µM and 20 µM), E. coli LPS (10 µg/mL), CHR (1 µM) and LUT (8.7 µM) alone and in their combinations. Cell viabilities (MTS assay) and extracellular (EC) hydrogen-peroxide (H2O2) production (Amplex red method) were evaluated. Intracellular (IC) reactive oxygen species (ROS) were assessed using a 2′-7′dichlorodihydrofluorescein diacetate (DCFH-DA) procedure. ELISA assay was used to evaluate IL-6 and IL-8 secretion. OTA decreased cell viabilities (p < 0.001) which could not be alleviated by LUT or CHR (p > 0.05); however, EC H2O2 production was successfully suppressed by LUT in IPEC-J2 cells (p < 0.001). OTA with LPS elevated the IC ROS which was counteracted by CHR and LUT (p < 0.001). IL-6 and IL-8 secretion was elevated by LPS + OTA (p < 0.001) which could be inhibited by LUT (p < 0.01 for IL-6; p < 0.001 for IL-8). Based on our results, CHR and LUT exerted beneficial effects on IC ROS levels and on cytokine secretion (LUT) in vitro; thus, they might be used as dietary and feed supplements to avoid OTA- and LPS-related health risks.