Maggot protein ameliorates dextran sulfate sodium-induced ulcerative colitis in mice.

Ulcerative colitis (UC) is a common chronic remitting disease but without satisfactory treatment. Maggots are known as a traditional Chinese medicine named as "wu gu chong". The aim of this study was to investigate the therapeutic effect of the maggot protein on dextran sulfate sodium (DSS)-induced colitis in C57BL/6 mice. In this study, female C57BL/6 mice were given sterile water containing 3% DSS to establish the model of UC. Mice were randomly divided into five groups: control group (sterile water), model group (DSS), treatment group (DSS + maggot protein), mesalazine group (DSS + mesalazine), and maggot protein group (sterile water + maggot protein).The mental state, defecate traits and changes of body weights were recorded daily. The disease activity index (DAI) as a disease severity criterion was calculated based on body weights and stool consistency and bleeding. All mice were sacrificed on the 12th day. Colon length, colon histological changes and inflammatory factors were analyzed and evaluated. The results showed that colitis mice were established successfully. Administration of maggot protein markedly suppressed the severity of UC compared with the DSS model group. Furthermore, maggot protein potently ameliorated DSS-induced weight loss, colon shortening and colon histological injury. Moreover, maggot protein exerted anti-inflammatory effects via inhibition of the activation of NFκB signaling pathway. In summary, treatment by maggot protein was able to improve not only the symptoms of colitis, but also microscopic inflammation in mice with DSS-induced colitis. This study may have implications for developing an effective therapeutic strategy for inflammatory bowel diseases.