Colorectal cancer (CRC) is a common gastrointestinal malignancy, the third most common malignancy, and the second most common cause of death in the world, accounting for 10% of the global cancer incidence and 9.4% of the total cancer-related death1,2. Genetic factors, chronic inflammation, high-fat diet, diabetes, and abnormal intestinal flora are risk factors for CRC3,4. Among them, inflammatory bowel disease, especially ulcerative coloproctitis (UC), is a clear risk factor for CRC5,6. UC-associated CRC (UC-CRC) is a transition process of inflammation, atypical hyperplasia, and cancer based on chronic inflammation of the colorectum, which is different from the typical adenoma-adenocarcinoma development model of CRC7,8. Compared with the general population, the risk of CRC is approximately 10-40 times higher in patients with inflammatory bowel disease9.
Currently, surgery is still the standard treatment for CRC, and depending on the location and stage of the tumor, radiation therapy, systemic drug therapy, or a combination of both are possible10. Although these traditional treatment modalities have made great progress, due to the high heterogeneity and recurrence rate of CRC, the prognosis is poor, and the treatment effect is not ideal11,12. Therefore, early detection, early diagnosis, and comprehensive treatment are key to improving the survival rate of CRC patients, and it is particularly important to pay attention to the transformation of UC to CRC. Over the years, traditional Chinese medicine (TCM) has attracted much attention in the treatment of UC-CRC or chronic gastritis due to its limited side effects and significant efficacy. Based on dialectical treatment, famous Chinese medicine practitioners of various generations have created a large number of classic prescriptions, such as Huangqi Jianzhong decoction13, Sijunzi decoction14, and Sishen pill15.
Liujunzi decoction (LJZD) originated from the works of Yi Xue Zheng Zhuan compiled in the Ming Dynasty and is a classic prescription in TCM16. As shown in Table 1, LJZD consists of six traditional herbs, including Codonopsis pilosula (Franch.) Nannf. (Dangshen), Poria cocos (Schw.) Wolf (Fuling), Atractylodes macrocephala Koidz. (Baizhu), Glycyrrhiza uralensis Fisch. (Gancao), Citrus reticulata Blanco (Chenpi) and Pinellia ternata (Thunb.) Breit (Banxia), which has the effect of replenishing qi and strengthening the spleen, drying dampness, and resolving phlegm. In modern clinical practice, it is often used to treat chronic gastritis, gastric ulcers, and duodenal ulcers. Modern pharmacological research has shown that LJZD and modified LJZD have high application value in the adjuvant treatment of UC and digestive tract cancer17,18,19.
At present, there are many ways to construct UC-CRC mouse models, but the azoxymethane (AOM)/dextran sulfate sodium (DSS) induced mouse model is the most widely used UC-CRC model; the clinical symptoms, morphological, and pathological observations have proved that the model is very similar to human UC-CRC20,21. The basic principle is to first induce carcinogenesis with chemical carcinogen AOM and then continuously expose mice to the inflammatory stimulation environment of DSS to simulate the continuous damage and repair of intestinal mucosal epithelium, thereby constructing a UC-CRC mouse model22. The aim of this study is to establish a mouse model of UC-CRC by intraperitoneal injection of AOM and cyclic stimulation of DSS in the short term and to evaluate the effect of the drug and the molecular mechanism of LJZD on UC-CRC in order to provide a scientific basis for the treatment of UC-CRC.