Benefit Effect of Dendrobium officinale Ultrafine Powder on DSS-Induced Ulcerative Colitis Rats by Improving Colon Mucosal Barrier

Abstract

Materials and methods: After intragastric administration of DOFP for 3 weeks, the rat UC model was made by the administration of 4% oral DSS solution for one week, and the drug was given at the same time. During the experiment, the disease activity index (DAI) score of the rats was regularly computed. At the end of the experiment, the blood routine indexes of rats were obtained. The histopathological changes in the colon were monitored by hematoxylin-eosin (H&E) and PAS staining and observation of ultrastructural changes in the colon by transmission electron microscope. Occludin expression in the colon was monitored by Western blot, the expression of claudin-1 and ZO-1 in the colon was detected by immunofluorescence, and the expression of TNF-α, IL-6, and IL-1β in the colon was detected by immunohistochemistry.

Results: The results firstly indicated that DOFP could significantly alleviate the signs and symptoms of the DSS-induced rats UC model, which manifested as improvement of body weight loss, increase of colon length, and improvement of the symptoms of diarrhea and hematochezia. Then, results from histopathology, blood routine examination, and transmission electron microscope analysis further implied that DOFP could dramatically reduce inflammatory cell infiltration and restore intestinal epithelial barrier integrity. In addition, the experiments of Western Blot analysis, immunofluorescence, and PAS staining also further confirmed that DOFP could markedly increase related protein expressions of the intestinal barrier and mucus barrier, as the expression of occludin, claudin-1, and ZO-1 in the colon significantly decreased. The experiments of immunohistochemistry confirmed that DOFP could markedly decrease protein expression levels of inflammatory cytokines TNF-α, IL-6, and IL-1β.

Conclusion: DOFP notably alleviated inflammatory lesions, repaired the colon mucosa damage by promoting the expression of tight junction proteins occludin, claudin-1, and ZO-1 and inhibiting the release of inflammatory factors TNF-α, IL-6, and IL-1β, and finally achieved the purpose of treating UC.

Figure 1

Characteristics of DOFC and DOFP. (a) SEM micrographs of DOFP. (b) SEM micrographs of DOFC.

Figure 2

DOFP treatment improves DSS-induced colitis in rats. (a) Representative photos of colon length. (b) Colon length. (c) Disease activity score. ^∗∗P < 0.01, compared with the normal group; ^#P < 0.05 and ^##P < 0.01, compared with the model group.

Figure 3

Effects of DOFP on histopathology of colitis rats. (a) Representative picture of colonic H&E staining (100×, 400×). (b) Colonic H&E staining score. (c) Representative picture of colonic PAS staining (400×). ^∗P < 0.05 and ^∗∗P < 0.01, compared with the normal group; ^#P < 0.05 and ^##P < 0.01, compared with the model group.

Figure 4

Effects of DOFP on TJ barrier function of colonic mucosa in UC rats. (a) Representative picture of the ultrastructure of colonic mucosa in colon. The arrow points to the tight junction, and the asterisk indicates microvilli. (b) Representative picture and semiquantitative statistical map of occludin protein bands in colon. (c) Representative picture of claudin-1 proteins expression with immunofluorescence in colon (400×). (d) Representative picture of ZO-1 proteins expression with immunofluorescence in colon (400×). ^∗P < 0.05 and ^∗∗P < 0.01, compared with the normal group; ^#P < 0.05 and ^##P < 0.01, compared with the model group.

Figure 5

Effects of DOFP on the inflammatory factors TNF-α, IL-6, and IL-1β of colonic mucosa in UC rats. (a) Representative picture of colonic IHC staining (400×). (b) Colon IHC average optical density statistics chart. ^∗P < 0.05 and ^∗∗P < 0.01, compared with the normal group; ^#P < 0.05 and ^##P < 0.01, compared with the model group.