Changes of Expressions of Claudin-1,-2,-4 in Experimental Colitis Rats / 胃肠病学

ABSTRACT

Background:Ulcerative colitis (UC)is a chronic inflammatory disorder. Studies have shown that intestinal injury of UC is related to changes of tight junction proteins. Aims:To investigate the expressions and localizations of tight junction protein claudin-1,-2,-4. Methods:Forty female Wistar rats were randomly divided into normal control group and model group. Rats in model group received 7. 5 mg/ mL oxazolone enema to induce experimental colitis. Rats received 0. 9%NaCl solution enema were served as normal controls. Macroscopic score and histological score were assessed. ELISA was used to determine serum and colon tissue inflammatory factor TNF-α,IL-4,IL-5,IL-10 levels. Protein expressions of tight junction protein claudin-1,-2,-4 were measured by immunohistochemistry and Western blotting. mRNA expressions of claudin-1,-2,-4 were determined by real-time PCR. Results:Compared with normal control group,macroscopic score and histological score were significantly increased (P < 0. 05),serum and colon tissue IL-4 and IL-5 levels were significantly increased (P < 0. 05)in model group,however,no significant differences in TNF-α and IL-10 levels were found between the two groups (P > 0. 05). mRNA and protein expressions of claudin-1,-4 were significantly decreased in model group than in normal control group (P < 0. 05),while mRNA and protein expressions of claudin-2 were significantly increased (P < 0. 05). Conclusions:Changes of distributions and expressions of tight junction protein claudin-1,-2,-4 are found in experimental colitis rats,which may lead to impaired epithelial barrier,and might be served as potential target for treatment of UC.