Establishment of the model

The model is established with reference to the research of Wang et al.11. Seventy healthy SD rats of SPF grade were used, 10 rats were randomly selected as a normal control group and the other 60 rats were numbered and their backs were shaved. Evenly smear the film on the shaved area of the back of rats with 2.0% DNCB acetone solution, 0.3 mL/time, once a day for 14 consecutive days (during this period, animals were fed normally). Pressing 0.25 mL/only on the 15th day, 0.1% DNCB ethanol (50% concentration) was intragastrically administered to rats (fasting without water for 24 hours before intragastric administration). On the 16th day, 6% acetic acid solution (0.7 mL) was administrated in the same way by intragastric injection on the previous day. The accurate time was set for 10 seconds, then flushed with 3 mL of normal saline. To establish a chronic rat UC model induced by DNCB combined with acetic acid. The normal group was operated in the above way and the modeling reagent was replaced by normal saline.