Algal Oil Rich in n-3 PUFA Alleviates DSS-Induced Colitis via Regulation of Gut Microbiota and Restoration of Intestinal Barrier

Abstract

Algal oil is rich in docosahexaenoic acid (DHA) and has various health benefits against human metabolic disorders and disease. This study aimed to investigate the effects of DHA algal oil on colonic inflammation and intestinal microbiota in dextran sulfate sodium (DSS)-induced colitis mice model. Male C57BL/6 mice was induced colitis by 2.5% DSS and followed by 2 weeks of treatment with algal oil (250 or 500 mg/kg/day). The colonic inflammation was assessed by colon macroscopic damage scores, and the degree of neutrophil infiltration was evaluated by measuring tissue-associated myeloperoxidase (MPO) activity in colonic mucosa. Tight junction proteins in the colonic tissue were measured by real-time PCR and western blot. Moreover, the intestinal microbiota and shot chain fatty acids (SCFAs) were estimated by bioinformatic analysis and GC, respectively. Colonic damage due to DSS treatment was significantly ameliorated by algal oil supplementation. In addition, algal oil significantly inhibited the increases of malondialdehyde (MDA) content, MPO activity, pro-inflammatory cytokines level and tight junction proteins expression in DSS-treated mice. Furthermore, supplementation of algal oil modulated the intestinal microbiota structure in DSS induced colitis mice by increasing the proportion of the unidentified_S24_7 and decreasing the relative abundance of unidentified_Ruminococcaceae, Clostridium and Roseburia. On the analysis of SCFAs, the caecal content of acetic acid, propionic acid, isobutyric acid, buturic, and the total SCFAs showed a significant increase in algal oil-administered mice. Together, these results suggested that algal oil rich in DHA inhibited the progress of DSS-induced colitis in mice by modulating the intestinal microbiota and metabolites and repairing the intestinal barrier, which may be applied in the development of therapeutics for intestinal inflammation.

Green Pea (Pisum sativum L.) Hull Polyphenol Extracts Ameliorate DSS-Induced Colitis through Keap1/Nrf2 Pathway and Gut Microbiota Modulation

“…Maintaining the normal expression of TJ proteins and the permeability of the intestinal epithelial barrier may be a crucial target for the treatment of IBD. Consistent with the previous results, the protein expression of claudin-1, occludin, and ZO-1 decreased after treatment with DSS [34]. However, treatment with the GPH extracts significantly increased the expression of the three TJ proteins, possibly due to the richness of flavonoids in the extracts.…”

“…A large number of studies have shown that IBD is related to the imbalance of intestinal immunity and inflammatory factors, such as IL-6, IL-1β and TNF-α, which are involved in the destruction of TJ proteins and are regulated by the NF-kB signaling pathway [2,31,34]. Therefore, controlling the production and release of inflammatory cytokines is considered a potential strategy for the treatment of IBD.…”

“…Gut microbiota plays an important role in maintaining the intestinal barrier function, and its imbalance is considered a key factor in the onset of IBD [34,37]. DSS can change the composition of the gut microbiota to aggravate colitis, which is manifested by inhibiting the abundance of probiotics and promoting the growth of harmful bacteria.…”

Dietary Supplementation throughout Life with Non-Digestible Oligosaccharides and/or n-3 Poly-Unsaturated Fatty Acids in Healthy Mice Modulates the Gut–Immune System–Brain Axis

“…This again indicates that the combination diet balances the effects of scGOS:lcFOS and n-3 PUFAs, which might be of valuable interest when combining these components in a healthy host or in models of disease. The main impact of n-3 PUFAs in this study was the modulated intestinal microbiota, which match finding of other studies [ 89 , 103 ]. To be able to explain the results, data on the n-3 PUFA metabolites in blood and/or brain tissues might have been useful.…”

Oyster (Crassostrea gigas) Extract Attenuates Dextran Sulfate Sodium-Induced Acute Experimental Colitis by Improving Gut Microbiota and Short-Chain Fatty Acids Compositions in Mice

“…These alternative therapies are of great interest because of their low side effects [7]. Among these, algal oil [8], propolis extract [9], peptides derived from tuna [10], taurine [11], and astragalin [12] have been reported to exert protective effects against experimental colitis induced by dextran sulfate sodium (DSS) in mice. Thus, the potential exists for IBD patients to have a greater variety of substances that are effective, in the form of alternative treatments.…”