Inflammatory bowel disease: Traditional knowledge holds the seeds for the future

Isofraxidin attenuates dextran sulfate sodium-induced ulcerative colitis through inhibiting pyroptosis by upregulating Nrf2 and reducing reactive oxidative species

BACKGROUND

Ulcerative colitis (UC), a non-specific gastrointestinal disease, is commonly managed with aminosalicylic acids and immunosuppressive agents to control inflammation and relieve symptoms, despite frequent relapses. Isofraxidin is a coumarin compound extracted from traditional Chinese medicine, exhibiting anti-inflammatory and antioxidant properties; however, its alleviating effect on UC remains unclear. Therefore, we investigated the mechanism of isofraxidin in lipopolysaccharide (LPS)-induced cell inflammation in human intestinal epithelial cell (HIEC) and human colorectal adenocarcinoma cells (Caco-2), as well as in dextran sulfate sodium (DSS)-induced UC in mice.

METHODS

We established colitis models in HIEC and Caco-2 cells and mice with LPS and DSS, respectively. Additionally, NLRP3 knockout mice and HIEC cells transfected with NLRP3 silencing gene and ML385 illustrated the role of isofraxidin in pyroptosis and oxidative stress. Data from cells and mice analyses were subjected to one-way analysis of variance or a paired t-test.

RESULTS

Isofraxidin significantly alleviated LPS-induced cell inflammation and reduced lactic dehydrogenase release. Isofraxidin also reversed DSS- or LPS-induced pyroptosis in vivo and in vitro, increasing the expression of pyroptosis-related proteins. Moreover, isofraxidin alleviated oxidative stress induced by DSS or LPS, reducing reactive oxidative species (ROS), upregulation nuclear factor erythroid 2-related factor 2 (Nrf2), and promoting its entry into the nucleus. Mechanistically, ML385 reversed the inhibitory effect of isofraxidin on ROS and increased pyroptosis.

CONCLUSION

Isofraxidin can inhibit pyroptosis through upregulating Nrf2, promoting its entry into the nucleus, and reducing ROS, thereby alleviating DSS-induced UC. Our results suggest isofraxidin as a promising therapeutic strategy for UC treatment.

Qing Hua Chang Yin alleviates chronic colitis of mice by protecting intestinal barrier function and improving colonic microflora

Background: Qing Hua Chang Yin (QHCY) is a famous formula of traditional Chinese medicine (TCM) and has been proven to have protective effect on ulcerative colitis. However, its protective effect and potential therapeutic mechanisms in chronic colitis remain unclear. The purpose of this study is to explore the effects and underlying mechanisms of QHCY on dextran sulfate sodium (DSS)-induced chronic colitis mice model. Methods: The chronic colitis model was established by administration of 2% DSS for three consecutive cycles of 7 days with two intervals of 14 days for recovery by drinking water. The experiment lasted 49 days. The DSS + QHCY group received QHCY administration by oral gavage at doses of 1.6 g/kg/d, DSS + Mesalazine group was administrated Mesalazine by oral gavage at doses of 0.2 g/kg/d. The control and DSS group were given equal volume of distilled water. The body weight, stool consistency and blood in stool were monitored every 2 days. The disease activity index (DAI) was calculated. The colon length was measured after the mice were sacrificed. The histomorphology of colonic tissues was checked by the HE and PAS staining. Immunohistochemistry was performed to detect the expressions of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6), tight junction proteins (ZO-1, occludin) and Mucin2 (MUC2). 16S rRNA sequencing analysis was conducted to study the diversity and abundance of gut microbiota changes. Results: QHCY treatment not only significantly attenuated DSS-induced the weight loss, DAI score increase, colon shortening and histological damage in mice, but also decreased the expression of pro-inflammatory cytokines in colonic tissues and increased the expression of ZO-1, occludin, and MUC2. Furthermore, QHCY enhanced the diversity of gut microbes and regulated the structure and composition of intestinal microflora in mice with chronic colitis. Conclusion: QHCY has a therapeutic effect on a murine model of chronic colitis. It can effectively reduce the clinical and pathological manifestations of colitis and prevent alterations in the gut microbiota.

Periplaneta americana extract ameliorates dextran sulfate sodium-induced ulcerative colitis via immunoregulatory and PI3K/AKT/NF-κB signaling pathways

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) with a low cure rate. Periplaneta americana is a traditional American Cockroach and reportedly has potential therapeutic roles for UC treatment; however, its mechanisms remain unclear. To address this, we investigated the therapeutic effects and underlying molecular mechanisms of Ento-A, a Periplaneta americana extract, in a dextran sulfate sodium (DSS)-induced chronic and recurrent UC mouse model. Ento-A treatment decreased pro-inflammatory cytokine secretion, disease activity index (DAI), colon mucosa damage index (CMDI), histopathological scores (HS), and increased colon length. Additionally, Ento-A effectively increased interleukin-4 (IL-4), and forkhead transcription factor protein 3 (Foxp3) expression levels, while it abated interferon-γ (IFN-γ) and IL-17 levels in spleen lymphocytes. Conversely, in mesenteric lymph nodes, IL-4 and Foxp3 expression were decreased, while IFN-γ and IL-17 expression was increased. Furthermore, Ento-A blocked p-PI3K, p-AKT,*and p-NF-κB activation. In conclusion, Ento-A improved UC symptoms and exerted therapeutic effects by regulating immune responses and inhibiting PI3K/AKT/NF-κB signaling.

Chitosan Ameliorates DSS-Induced Ulcerative Colitis Mice by Enhancing Intestinal Barrier Function and Improving Microflora

Ulcerative colitis (UC) has been identified as one of the inflammatory diseases. Intestinal mucosal barrier function and microflora play major roles in UC. Modified-chitosan products have been consumed as effective and safe drugs to treat UC. The present work aimed to investigate the effect of chitosan (CS) on intestinal microflora and intestinal barrier function in dextran sulfate sodium (DSS)-induced UC mice and to explore the underlying mechanisms. KM (Kunming) mice received water/CS (250, 150 mg/kg) for 5 days, and then received 3% DSS for 5 days to induce UC. Subsequently, CS (250, 150 mg/kg) was administered daily for 5 days. Clinical signs, body weight, colon length, and histological changes were recorded. Alterations of intestinal microflora were analyzed by PCR-DGGE, expressions of TNF-α and tight junction proteins were detected by Western blotting. CS showed a significant effect against UC by the increased body weight and colon length, decreased DAI (disease activity index) and histological injury scores, and alleviated histopathological changes. CS reduced the expression of TNF-α, promoted the expressions of tight junction proteins such as claudin-1, occludin, and ZO-1 to maintain the intestinal mucosal barrier function for attenuating UC in mice. Furthermore, Parabacteroides, Blautia, Lactobacillus, and Prevotella were dominant organisms in the intestinal tract. Blautia and Lactobacillus decreased with DSS treatment, but increased obviously with CS treatment. This is the first time that the effect of original CS against UC in mice has been reported and it is through promoting dominant intestinal microflora such as Blautia, mitigating intestinal microflora dysbiosis, and regulating the expressions of TNF-α, claudin-1, occludin, and ZO-1. CS can be developed as an effective food and health care product for the prevention and treatment of UC.

Therapeutic effect of imiquimod on dextran sulfate sodium-induced ulcerative colitis in mice

BACKGROUND

Imiquimod is a Toll-like receptor-7 agonist that regulates immunity and can be used as an immune adjuvant. Ulcerative colitis has a close correlation with immune disorder.

AIM

To investigate the therapeutic effect of imiquimod on dextran sulfate sodium (DSS)-induced colitis and explore the underlying mechanisms.

METHODS

C57BL/6J C57 mice received 3% DSS for 7 days to induce ulcerative colitis. Groups of mice were intraperitoneally injected with dexamethasone (DXM, 1.5 mg/kg) or imiquimod (IMQ, 30 mg/kg) at the same time daily. During the experimental period, clinical signs, body weight, stool consistency and visible fecal blood were monitored and recorded daily; colitis was evaluated by disease activity index (DAI) score and by histological score. At the conclusion of the experiment, the level of colonic myeloperoxidase (MPO) activity and the serum levels of the cytokines tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6) and interleukin 10 (IL-10) were measured.

RESULTS

Administration of 3% DSS for 7 days successfully induced acute colitis associated with diarrhea, bloody mucopurulent stool, body weight decreases, and other changes. Colitis severity was significantly ameliorated in the IMQ treatment groups, as determined by hematoxylin-eosin (HE) staining and histopathological scores. Moreover, IMQ significantly reduced the activity of MPO in colonic tissue and the serum levels of inflammatory cytokines, increased colon length and spleen weight, and effectively inhibited microscopic damage to the colon tissue.

CONCLUSION

IMQ had beneficial effects on DSS-induced ulcerative colitis, supporting its further development and clinical application in ulcerative colitis.

Natural Nuclear Factor Kappa Beta Inhibitors: Safe Therapeutic Options for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic and debilitating condition classified as ulcerative colitis and Crohn's disease. IBD usually happens as result of immune dysfunction in the intestinal mucosa resulting in epithelial barrier dysfunction, which leads to exposure of the mucosal immune system to luminal antigenic material. This results in activation of inflammation, which is our bodies natural defense system; however, chronic inflammation leads to barrier dysfunction, which triggers a cycle of inflammation and further barrier dysfunction. This barrier breakdown results in the uncontrolled progression of IBD throughout the intestine. Despite the therapeutic advances made over the last decade, the current first line of treatment of IBD is limited to immunosuppressive and anti-inflammatory drugs, which need to be taken regularly and have significant side effects to the patients. Prolonged inflammation may increase the risk of intestinal malignancy. The role of nuclear factor kappa beta (NF-κβ) has been established in the regulation of innate immunity and inflammation. NF-κβ has also shown to be involved in critical events linking inflammation and cancer development. Recent investigations suggest that the NF-κβ signaling cascade may be the central mediator of gastrointestinal inflammation in IBD and malignancies including esophageal, gastric, and colorectal cancers. In this review, the therapeutic potential of natural NF-κβ inhibitors as safe therapeutic options for the treatment of IBD will be discussed.