Mycotoxins and thermal processing hazards are common contaminants in various foods and cause severe problems in terms of food safety and health. Combined use of acrylamide (AA) and ochratoxin A (OTA) would result in more significant intestinal toxicity than either toxin alone, but the underlying mechanisms behind this poor outcome remain unclear. Herein, we established the co-culture system of Caco-2/HT29-MTX cells for simulating a real intestinal environment that is more sensitive to AA and OTA, and showed that the combination of AA and OTA could up-regulate permeability of the intestine via increasing LY permeabilization, and decreasing TEER, then induce oxidative stress imbalance (GSH, SOD, MDA, and ROS) and inflammatory system disorder (TNF-α, IL-1β, IL-10, and IL-6), thereby leading a rapid decline in cell viability. Western blot, PAS- and AB-staining revealed that AA and OTA showed a synergistic effect on the intestine mainly through the disruption of tight junctions (TJs) and a mucus layer. Furthermore, based on correlation analysis, oxidative stress was more relevant to the mucus layer and TJs. Therefore, our findings provide a better evaluation model and a potential mechanism for further determining or preventing the combined toxicity caused by AA and OTA.
Pectin is a structurally complex heteropolysaccharide that affects intestinal microorganisms and mucin O -glycans. The present study employed an in vitro model to investigate dynamic changes in microbiota during pectin fermentation. Residual pectin fragments arising from its fermentation were applied to HT29-MTX cells to study the effect of pectin structure on mucin O -glycosylation. Prevotella , Bacteroides , and Parabacteroides were found to preferentially degrade galactose, arabinose, and on the rhamnogalacturonan RG-I side chain region and methyl esterification groups of pectin. Bifidobacterium , Enterococcus , Megamonas , and Dorea metabolized the galacturonic HG region on pectin to produce butyrate. All pectin fragments were found to up-regulate total O -glycans (1.55–2.73 fold) and neutral O -glycans (1.11–1.49 fold) on HT29-MTX mucins. The large HG fragment (81.04 kDa) increased significantly the amount of non-fucosylated glycans (by 2.46-fold); whereas the small HG fragment (16.02 kDa) promoted fucosylated (by 9.25 fold), and especially di-fucosylated O -glycans. Collectively, these results demonstrate that gut microorganisms degrade pectin fragments in the following order of utilization: RG-I, RG-II, and HG. The small fragment of HG improves the expression of fucosylated O -glycans in HT29-MTX cells, mainly owing to an increase in di-fucosylated O -glycans.
危险品化学品经营许可证（带存储）