乳酸菌对肠上皮细胞侵袭性大肠杆菌损伤的保护作用

Qingchang Suppository up-regulates the expression of tight junction proteins ZO-1 and occludin in experimental ulcerative colitis in rats

AIM: To observe the effect of Qingchang Suppository (QS) on the expression of tight junction proteins zonula occluden-1 (ZO-1) and occludin in the colon of rats with trinitrobenzenesulfonic acid (TNBS)-induced ulcerative colitis (UC).

METHODS: Thirty-six SD rats were randomly and equally divided into six groups: normal control group, model group, SASP group, high-, medium- and low-dose QS groups. UC was induced in rats with TNBS. The expression of tight junction proteins ZO-1 and occludin in the colon was examined by immunofluorescence.

RESULTS: The immunofluorescence signals of ZO-1 and occludin were irregularly distributed and appeared disrupted in rats with UC. The average optical density of ZO-1 and occludin immunofluorescence, as calculated using image analysis software, were decreased obviously in UC rats compared to normal controls (1.802 ± 1.304 vs 3.145 ± 0.110; 0.568 ± 0.063 vs 1.538 ± 0.220, both P < 0.01). Treatment with QS up-regulated the expression of ZO-1 and occludin in rats with UC (both P < 0.01).

CONCLUSION: QS exerts a beneficial effect against TNBS-induced UC in rats possibly by modulating intestinal mucosal barrier and decreasing increased intestinal permeability.

Advances in research of intestinal epithelial tight junctions and intestinal permeability

Intestinal epithelial tight junctions are a structural basis for the intestinal barrier and play an important role in the regulation of intestinal permeability. Increased intestinal permeability caused by the destruction of tight junctions may result in bacterial translocation, systemic inflammatory response, and multiple organ dysfunction syndrome. In this paper, we review the structure and function of tight junctions, factors affecting intestinal permeability, and measures for improving the dysfunction in intestinal permeability.

Yoghourt accelerates the recovery of gastric ulcer in rats

AIM: To investigate whether yoghourt accelerates the recovery of gastric ulcer in rats.

METHODS: Gastric ulcer was induced in rats by intraperitoneal injection of reserpine at a dose of 0.5 mL/kg. Rats with gastric ulcer were then divided into three groups: yoghourt group, milk group and sodium chloride group, which were intragastrically given yoghourt, milk and sodium chloride once (5 mL/kg) every other day, respectively. All animals were killed on day 7 after administration. The extent of mucosal lesions was evaluated based on Guth score. The levels of prostaglandin E2 (PGE2) and superoxide dismutase (SOD) in gastric mucosa were measured.

RESULTS: Punctiform erosion and hemorrhage were observed by naked eyes in rats of each group. Guth score was significantly lower in the yoghourt group than in the milk group (1.33 ± 0.577 vs 5.00 ± 1.323, P < 0.05) though there was no significant difference between the yoghourt group and sodium chloride group (P > 0.05). Epithelial cell necrosis and shedding and neutrophil infiltration of the propria lamina were observed by microscopy. The lesions in rats of the sodium chloride group were more severe than those in rats of the yoghourt group. The content of PGE2 in gastric mucosa was significantly higher in the yoghourt group than in the sodium chloride group (248.6 ± 43.73 vs 79.52 ± 31.74, P < 0.05) though no significant difference was observed between the yoghourt group and the milk group. The content of SOD in gastric mucosa was significantly lower in the yoghourt group than in the milk group (148.1 ± 2.18 vs 156.6 ± 1.66, P < 0.01), but showed no significant difference between the yoghourt group and the sodium chloride group.

CONCLUSION: Yoghourt exerts a positive effect on the recovery of gastric ulcer in rats possibly by increasing PGE2 content and decreasing SOD content.