Objective: The mechanism of preventing ulcerative colitis associated carcinogenesis (UCAC) by Jianpi Qingre Huoxue decoction was discussed by observing the changes of β-catenin and T cell factor-4(TCF-4)in colon mucosa. Method: One hundred and twenty BALB/c rats were randomly divided into six groups:normal group

model group

positive control group

low dosage

mild dosage and high dosage groups of Jianpi Qingre Huoxue

20 rats in each group. Except normal group

the other groups were intraperitoneal injected with 0.4% dimethylhydrazine (DMH) 20 mg·kg-1 by skin and peritoneal once a week. After intraperitoneal injection of DMH

those groups were given orally 3% dextran sulfacte sodium(DSS) for one week. The model group was treated with normal saline by intragastric administration for sixteen weeks. The positive control group was treated with mesalazine decoction for sixteen weeks. The intervention group was treated with different dosage of Jianpi Qingre Huoxuo decoction by intragastric administration for sixteen weeks. The colon histomorphology was assayed by naked eyes and light microscope. The ultra microstructure was checked by electron microscope. The expression of β-catenin and TCF-4 was detected by immunohistochemistry and western-blot and Real-time PCR. Result: The changes of high-grade intraepithelial neoplasia and partical carcinogenesis were found in model group by electron microscope

Meanwhile

a lot of epithelial cell of specimen size and arranged in disorder were found in colon mucosa of blank group

at same time

the irregular cell mucleus and the mucleolued of increasment and upward displacement appeared.However

the colon mucosa damage obviously improved in intervention group compared withmodel group. Colon mucosa is characterized by hyperemia and swelling by light microscope

small amout mild atypical hyperplasia and lymphoid follicle could be found

but the ulceration and carcinogenesis could not be found. By electron microscope

epithelial cell became smaller

at the same time

condensation of the nuclear chromatin

shrinkage and nucleus membrane and apoptofic bodies were found in intervention groups. The colonic mucosa damage was improved obiviously in intervention groups

compared with the black group (P<0.05).The expression of β-catenin and TCF-4 was increased in model group

meanwhile

the expression of β-catenin and TCF-4 was declined in intervention groups

compared with the model group (P<0.05). Conclusion: The Jianpi Qingre Huoxue decoction may exert a preventing effect on ulcerative colitis associated carcinogenesis through promoting inflammation laxation

inducing cell apoptosis

regulating the expression of β-catenin and TCF-4.