Walnut Oil Alleviates Intestinal Inflammation and Restores Intestinal Barrier Function in Mice

Abstract

Ulcerative colitis belongs to inflammatory bowel diseases, which is a group of chronic disorders of the gastrointestinal tract. It is a debilitating condition with a wide range of symptoms including rectal bleeding, diarrhea, and visceral pain. Current dietary habits often lead to imbalance in n-6/n-3 polyunsaturated fatty acids (PUFA) in favor of n-6 PUFA. Recent data showed the potential anti-inflammatory advantage of n-3 PUFA. Walnut oil (WO) is rich in those fatty acids and mainly consists of linoleic and linolenic acids that may act via free fatty acids receptors (FFARs). We assessed the anti-inflammatory effect of WO in the mouse model of dextran sulfate sodium (DSS)-induced colitis. Moreover, we examined changes in the expression of tight junction proteins (TJ), pro-inflammatory cytokines, and FFAR proteins in the inflamed mouse colon. WO improves the damage score in inflamed tissue, significantly restoring ion transport and colonic wall permeability. Inflammation caused changes in TJ, FFAR, and pro-inflammatory gene proteins expression, which WO was able to partially reverse. WO has anti-inflammatory properties; however, its exact mechanism of action remains unclear. This stems from the pleiotropic effects of n-3 PUFA ligands associated with receptor distribution and targeted signaling pathways.

Activation of Free Fatty Acid Receptor 4 Affects Intestinal Inflammation and Improves Colon Permeability in Mice

“…FFAR4 restored the expression of OCLN, CLDN1, CLDN2, and CLDN10. Similar results were also obtained with the administration of walnut oil, which is believed to activate FFAR4 [ 22 ].…”

“…Consequently, we envisage anti-IBD interventions based on nutrients especially for those who prefer to refrain from synthetic drugs yet choose the treatment that provides similar efficacy. In line, we previously showed that treatment with a diet enriched with walnut oil, rich in FFAR4 agonists, such as α-linolenic acid and high n-3/n-6 omega FFAs ratio, alleviates intestinal inflammation in mice [ 22 ]. Colitis was also improved by fish oil, rich in n-3 LCFA, in two other studies [ 44 , 45 ].…”

“…Mice were randomized, and colonic inflammation was induced, as described before [ 22 ]. On day 0 of the experiment, DSS (4% w / v ; molecular weight 40,000 (MP Biomedicals, Aurora, OH, USA, Lot No.…”

Natural Compounds of Marine Origin as Inducers of Immunogenic Cell Death (ICD): Potential Role for Cancer Interception and Therapy

“…The polyunsaturated fatty acids from Schizochytrium induce microbiota stimulation and mucin release [ 97 ]. In recent studies, it was demonstrated how PUFAs disrupt membrane domain organization through changes in lipid rafts activating specific signalling networks through the microbiota stimulation and cytokines release [ 127 ], and anti-inflammatory activities [ 128 ].…”

Efficient Stool Collection Methods for Evaluating the Diarrhea Score in Mouse Diarrhea Models

“…However, considering that most mouse experiments do not deal with a small number of mice, but a large number of mice, it is not that practical. Another accurate way would be to evaluate the stool in the rectum or the large bowel after sacrificing the mouse (67)(68)(69). However, it can only evaluate the diarrhea score once per mouse, and serial evaluations over several days are difficult.…”