Università degli Studi di Milano, DeFENS - Department of Food, Environmental and Nutritional Sciences, Via Celoria 2, 20133 Milano, Italy.
School of Food and Agriculture, University of Maine, Orono, Maine, USA.
Food Funct. 2023 Aug 14;14(16):7387-7399. doi: 10.1039/d3fo00835e.
Increasing evidence links the impairment of intestinal permeability (IP), a feature of the intestinal barrier, to numerous dysmetabolic and dysfunctional conditions. Several host and environmental factors, including dietary factors, can negatively and/or positively affect IP. In this regard, polyphenol-rich foods including berries have been proposed as potential IP modulators. However, the exact mechanisms involved are not yet fully elucidated. The aim of the present study was to evaluate the effect of a wild blueberry (WB; ) powder, naturally rich in polyphenols, to affect Caco-2 cell monolayer permeability and to identify the potential mechanisms in modulating the IP process. Caco-2 cells were incubated with TNF-α (10 ng mL), as a pro-inflammatory stimulus, and supplemented for 24 hours with different concentrations (1 and 5 mg mL) of WB powder. The integrity of the intestinal cell monolayer was evaluated by measuring the transepithelial electrical resistance (TEER) and the paracellular transport of FITC-dextran. In addition, the production of the tight junction proteins, such as claudin-1 and occludin, as well as protein carbonyl and 8-hydroxy 2 deoxyguanosine, as oxidative stress markers, were quantified in the supernatant by ELISA kits. Overall, the treatment with WB powder (5 mg mL) mitigated the loss of Caco-2 cell barrier integrity, as documented by an increase in TEER and a reduction in FITC values. This modulation was accompanied by an upregulation of claudin-1 and a reduction of 8-OHdG. Conversely, no effect was documented for the lower concentration (1 mg mL) and the other IP markers, as well as oxidative stress markers analysed. In conclusion, our findings suggest a potential role of WB in the modulation of cell barrier integrity. This modulation process could be attributed to an increase in claudin-1 expression and a reduction in 8-OHdG. Further studies should be performed to corroborate the results obtained. In addition, since the effects were observed at doses of WB achievable with the diet, these findings should be substantiated also through approaches.
越来越多的证据表明，肠道通透性（IP）的损害是肠道屏障的一个特征，与许多代谢和功能障碍的情况有关。一些宿主和环境因素，包括饮食因素，可以对 IP 产生负面影响和/或正面影响。在这方面，富含多酚的食物，包括浆果，已被提议作为潜在的 IP 调节剂。然而，确切的机制尚未完全阐明。本研究旨在评估富含多酚的野生蓝莓（WB；）粉对 Caco-2 细胞单层通透性的影响，并确定调节 IP 过程的潜在机制。Caco-2 细胞用 TNF-α（10 ng mL）孵育，作为促炎刺激物，并在 24 小时内用不同浓度（1 和 5 mg mL）的 WB 粉补充。通过测量跨上皮电阻（TEER）和 FITC-葡聚糖的旁分泌转运来评估肠道细胞单层的完整性。此外，通过 ELISA 试剂盒定量上清液中紧密连接蛋白（如 Claudin-1 和 Occludin）以及氧化应激标志物（如蛋白羰基和 8-羟基 2 脱氧鸟苷）的产生。总的来说，WB 粉（5 mg mL）的处理减轻了 Caco-2 细胞屏障完整性的丧失，这体现在 TEER 的增加和 FITC 值的降低。这种调节伴随着 Claudin-1 的上调和 8-OHdG 的减少。相反，较低浓度（1 mg mL）和其他 IP 标志物以及分析的氧化应激标志物没有记录到效果。总之，我们的研究结果表明 WB 在调节细胞屏障完整性方面可能发挥作用。这种调节过程可能归因于 Claudin-1 表达的增加和 8-OHdG 的减少。应进行进一步的研究来证实所获得的结果。此外，由于在饮食中可以达到 WB 的剂量下观察到了这些效果，因此还应通过 方法来证实这些发现。
