Lycium barbarum Polysaccharides and Capsaicin Alleviate Dextran Sulfate Sodium‐Induced Ulcerative Colitis in Rats via Anti‐Inflammatory Effect

Abstract

Ulcerative colitis (UC), a chronic remittent inflammatory condition, leads to inflammation and ulcer in the colon and rectum. This study investigated the protective effects of Lycium barbarum polysaccharides (LBP, 51.25% polysaccharides) from wolfberry extract and capsaicin (CAP, 85% capsaicin) from cayenne pepper extract on UC induced by dextran sulfate sodium (DSS) in rats. Sprague-Dawley rats were divided in to 5 groups: control, UC, UC treated with 100 mg/kg bw LBP (LBP), UC treated with 12 mg/kg bw CAP (CAP), and UC treated with a combination of 50 mg/kg bw LBP and 6 mg/kg bw CAP (MIX) groups. Treatment with LBP and/or CAP was orally administered by gavage from week 1 to week 4, and 5% DSS was given in drinking water for 6 days during week 3 to induce UC. After 4-week treatment, rats were sacrificed, and colon length, colon weight, disease activity index (DAI), and colonic levels of interferon-γ (IFN-γ), interleukin (IL)-17A, and IL-22 were measured. The DSS group induced UC symptoms, elevated DAI score, shortened colon length, and increased colon weight to length ratio compared with the control group. The LBP, CAP, and MIX groups significantly decreased DAI scores on days 5 and 6 during the DSS-induced period, and significantly reversed a decrease in colon length and an increase in colon weight to length ratio caused by DSS. The DSS group significantly increased proinflammatory cytokines IFN-γ, IL-17A, and IL-22 levels in the colon. The LBP and CAP groups significantly decreased colonic IFN-γ, IL-17A, and IL-22 levels compared with the DSS group, however, the MIX group only significantly decreased colonic IL-22 levels. Our results suggested that administration of LBP and/or CAP attenuates DSS-induced UC symptoms and improves colon length through suppression of colon inflammation.