Graduate Program on Food Science and Technology, Center of Rural Sciences, Federal University of Santa Maria, 97105-900 Santa Maria, Rio Grande do Sul, Brazil; Federal Institute of Education, Science, and Technology Farroupilha, 97555-000 Alegrete, Rio Grande do Sul, Brazil.
School of Food Engineering, Department of Food and Nutrition, University of Campinas, Campinas, São Paulo 13083-862, Brazil.
Food Res Int. 2019 Sep;123:425-439. doi: 10.1016/j.foodres.2019.04.068. Epub 2019 Apr 30.
Inflammatory bowel diseases are characterized by impaired intestinal barrier function. This study aimed to evaluate the effects of grape peel powder (GPP) and its bioactive rich-fractions on the barrier function and colonic injury in a model of colitis induced by 2,4,6 trinitrobenzene sulfonic acid (TNBS). Wistar rats received diets supplemented with either GPP (8%), extractable polyphenols (EP), non-extractable polyphenols-rich fraction (NEP-F), or polyphenols-poor, fiber-rich fraction (F) from grapes at amounts equivalent to the GPP group during 15 days before and for 7 days after colitis induction. NEP-F has decreased the extension of colonic lesion but the other grape peel bioactive fractions did not protect against macroscopic or microscopic colonic damage, EP diet increased macroscopic colonic damage. GPP, EP, and NEP-F reduced claudin-2 mRNA expression, whereas GPP and F fraction increased occludin and ZO-1 mRNA expression. All experimental diets reduced the colitis-triggered increase of MMP-9 mRNA expression. Colitis reduced by 30% the production of cecal short-chain fatty acids (SCFA). GPP and NEP-F completely protected against this effect, whereas F fraction was ineffective. Only GPP and NEP-F were able to decrease the upregulation of GRP94 mRNA triggered by colitis. Dietary fiber seems to reestablish the intestinal barrier function, whereas fiber-bound phenolics were able to restore cecal metabolism to produce beneficial metabolites like SCFA and to reduce the activation of the unfolded protein response.
炎症性肠病的特征是肠道屏障功能受损。本研究旨在评估葡萄皮粉（GPP）及其生物活性丰富部分对 2,4,6-三硝基苯磺酸（TNBS）诱导的结肠炎模型中屏障功能和结肠损伤的影响。Wistar 大鼠在结肠炎诱导前 15 天和诱导后 7 天内接受补充 GPP（8%）、可提取多酚（EP）、非可提取多酚丰富部分（NEP-F）或葡萄多酚贫乏、富含纤维部分（F）的饮食，其添加量相当于 GPP 组。NEP-F 减少了结肠病变的延伸，但其他葡萄皮生物活性部分不能防止宏观或微观结肠损伤，EP 饮食增加了宏观结肠损伤。GPP、EP 和 NEP-F 降低了 Claudin-2 mRNA 的表达，而 GPP 和 F 部分增加了 Occludin 和 ZO-1 mRNA 的表达。所有实验饮食均降低了结肠炎触发的 MMP-9 mRNA 表达增加。结肠炎使盲肠短链脂肪酸（SCFA）的产生减少了 30%。GPP 和 NEP-F 完全防止了这种作用，而 F 部分则无效。只有 GPP 和 NEP-F 能够降低结肠炎引发的 GRP94 mRNA 的上调。膳食纤维似乎重建了肠道屏障功能，而纤维结合的酚类物质能够恢复盲肠代谢，产生有益的代谢物，如 SCFA，并减少未折叠蛋白反应的激活。
