EGCG ameliorates colitis in DSS-induced UC mice
The typical features in the DSS-induced mice model of UC have sustained body weight loss, diarrhea, and rectal bleeding16. The colitis was induced in mice by administration of 3% DSS for 8days as described in methods. We found that the bodyweight of mice in DSS group continued to decrease significantly from day6 (figure2A) and EGCG administration could dramatically improve body weight loss in mice by treat with high dose (figure1A, p<0.05). The colon shortening was restored by EGCG therapy compared with DSS treatment group (figure2B and 2C). The spleen weight was generally measured as an indirect marker of inflammation in all experiment groups. Different concentrations EGCG could significantly reversed the DSS-mediated increase in the spleen index (P<0.05, Figure 2D). Furthermore, the DAI score, which is used as indicator to assessing the severity of colitis, increased distinctly after DSS treatment and it was markedly lower in the HE group (figure2E and 2F). In addition, we also observed epithelial crypt damage, mucosa edema, disappearance of intestinal crypts and goblet cells, and inflammatory cell infiltration by histopathological analysis using H&E staining to assessing severity of colonic ulceration and inflammation during experiment groups. The DSS group was sharp contrast to the normal group (figure 2G) and EGCG could exhibited obvious protection of mucosa damage and less histological inflammation (figure 2G), which showed a lower histopathological score (figure 2H). Thus, these data confirm that EGCG exerts therapeutic effects on DSS-induced colitis.