Objective To observe the protective effect of epigallocatechin gallate (EGCG) on dextran sulfate sodium- (DSS-) induced ulcerative colitis in rats and to explore the roles of TLR4/MyD88/NF-was normal or decreased [10], suggesting that the occurrence and development of UC were strongly associated with the imbalance of Th1 and Th2 cells. previous study [17]. The rats were allowed free access to solution containing 5% DSS (molecular weight 5000) for 7 days and then given distilled water for 14 days. After model establishment, the rats were intraperitoneally injected with EGCG 50?mg/kg/d, for 10 consecutive days. 2.3. Disease Activity Index (DAI) According to body weight, stool, and blood in the stool, the rats were scored. Score 0 indicates no weight loss, normal stool, and no blood in the stool; score 1 indicates 1%C5% weight loss, loose stools, and fecal occult blood; score 2 indicates PRL 5%C10% weight loss, loose stools, and fecal occult blood; score 3 indicates 10%C15% weight loss, watery stool, and gross blood stool; score 4 indicates more than 15% weight loss, watery stool, and gross blood stool. 2.4. Severity of Colonic Mucosal Injury In accordance with Luketal’s standards, score 0 indicates normal and no injury; score 1 indicates hyperemia and no ulcer; score 2 indicates hyperemia, bowel wall thickening, and no ulcer; score 3 indicates one small ulcer 2-Methoxyestradiol kinase activity assay focus in 0-1?cm diameter; score 4 indicates big ulcer focus in 1-2?cm diameter and no bowel canal adhesion to the surrounding organs; score 5 indicates ulcer focus in 1-2?cm diameter, bowel thickening, and severe adhesion to adjacent organs. 2.5. Hematoxylin-Eosin Staining All rats were sacrificed after EGCG withdrawal; rat colonic mucosa was fixed in 10% formaldehyde, decalcified, dehydrated, permeabilized, 2-Methoxyestradiol kinase activity assay embedded in wax, and sliced into 5?at room temperature in the dark for 45 minutes, washed with 1x BD perm/wash buffer, and resuspended with 300?or Dunnett- 0.05 was considered statistically significant. 3. Results 3.1. EGCG Lessens Colonic Mucosal Injury in UC Rats Compared with the sham group, DAI score was significantly higher in the UC group ( 0.05) (Figure 1(b)). Compared with the UC group, DAI score was significantly decreased in the EGCG group ( 0.05). In the sham group, the colonic surface of rats was smooth with no bleeding or ulceration. Intestinal hemorrhage, ulcer, and intestinal adhesions were seen in UC rats. After EGCG intervention, small ulcer foci were visible in the colonic tissue (Figure 1(a)). It was found that the score of colonic mucosal injury was significantly increased in the UC group and diminished after EGCG intervention (Figure 1(c)). Hematoxylin-eosin staining results demonstrated that mucosal epithelial cell degeneration/necrosis and inflammatory cell infiltration were observed in the UC group (Figure 1(d)). Mild epithelial cell degeneration/necrosis and small amounts of inflammatory cells were distinct in the EGCG group. Histomorphological score of mucosa in rats was significantly lower in the UC group than in the sham group. After intervention with TLR4 inhibitor, scores and HE staining were not significantly different compared with the UC group ( 0.05). Open in a separate window Figure 1 The UC model was established; the rats were intraperitoneally injected with EGCG 50?mg/kg/d for 10 consecutive days. The rat colonic tissue was collected, and colonic mucosal injury was observed (a). The rats were scored based on body weight, stool, and blood in the stool. (c) In accordance with Luketal’s standards, colonic mucosal injury was scored. (d) The rat colonic tissue was collected, and the colonic pathological changes were observed after the HE staining (b). Data were collected from the control group, UC group, EGCG group, and TLR4 group (= 10). Compared with control group, 0.05. Compared with UC group, # 0.05. 3.2. EGCG Suppresses Inflammatory Response 2-Methoxyestradiol kinase activity assay in UC Rats Serum IL-2, IFN-levels were higher ( 0.05), but IL-4 and IL-10 levels were lower in.