Ameliorative Effect of DL-tryptophan on Acute Colitis in Mice

DU Mengyuan; DING Man; HE Shuiling; LI Zhuoyu

doi:10.13982/j.mfst.1673-9078.2025.11.1295

Abstract：The ameliorative effect of DL-tryptophan on dextran sulphate sodium(DSS)-induced ulcerative colitis(UC)in mice was investigated.The alcohol extract of quinoa was obtained using the ultrasonic-assisted extraction method,followed by isolation and purification.DL-tryptophan was identified as the primary component through compositional analysis.The anti-inflammatory effect of quinoa DL-tryptophan was assessed using RAW264.7 macrophage cells to establish an inflammation model.Wild-type C57BL/6 mice were used as study subjects and were administered 50 mg/kg of pure DL-tryptophan daily through oral gavage;the anti-inflammatory effect of quinoa DL-tryptophan was then evaluated using the DSS-induced UC model.The ameliorative effects of DL-tryptophan were assessed by monitoring changes in body weight and surface characteristics,assessing Disease Active Index(DAI)scores,measuring colon length,and performing hematoxylin and eosin staining and immunofluorescence staining.The expression of tumor necrosis factor(TNF-α)and interleukin 1β(IL-1β)in the colon tissues of the mice were detected using enzyme-linked immunosorbent assay to assess the ameliorative effect of DL-tryptophan on DSS-induced UC mice.Compared with the model group,the DAI score in the DL-tryptophan group decreased by 50.64%,whereas the average body weight and colon length increased by 5.03 g and 2.23 cm,respectively.In addition,the DL-tryptophan group showed decreased number of intestinal cup cells and improved mucosal damage,and the expression levels of TNF-α,IL-1β and other inflammatory factors in the colon tissue significantly decreased(P<0.01).The expression of tight junction proteins claudin-1,occludin,and ZO-1 in intestinal epithelial cells was recovered.In summary,DL-tryptophan ameliorates DSS-induced UC in mice by decreasing the secretion of inflammatory factors and restoring the expression of tight junction proteins,thereby alleviating intestinal inflammatory responses.