Establishment and evaluation of a rat model of ulcerative colitis with syndrome of dampness stagnancy due to spleen deficiency

To establish a rat model of ulcerative colitis with syndrome of spleen deficiency and dampness stagnancy.Sixty rats were divided into normal control group, ulcerative colitis group, ulcerative colitis with syndrome of spleen deficiency and dampness stagnancy group (model group) and strengthening spleen for resolving dampness group. Ulcerative colitis in rats was induced by enema containing trinitrobenzene sulfonic acid (TNBS) and ethanol. The rats in the model group were suffered from standing in water, limiting sleeping time and abnormal diet based on administration of TNBS and ethanol. The rats in the spleen strengthening and dampness resolving group were gastrically administered with Shenlin Baizhu Powder, a compound traditional Chinese herbal medicine. Symptoms, signs and pathological changes in colon tissue of rats were observed after modeling. The levels of interleukin (IL)-6, IL-8 and tumor necrosis factor-α (TNF-α) in serum of rats were measured by enzyme-linked immunosorbent assay.The rats in the model group showed lethargy, poor appetite, loss of energy, diarrhea and bloody stool. Their body weight decreased significantly compared with the normal control group, and similar changes were found in the comparison of food intake, drinking amount, urine amount, stool wet weight and assay of spontaneous activity (P<0.05). When observed under a light microscope, the colon tissues of rats in the model group showed mucosal edema, congestion, inflammatory cell infiltration and ulceration. The degree of colon injury and IL-6, IL-8 and TNF-α levels were significantly increased (P<0.05) as compared to those in the normal control group. The changes mentioned above were improved by Shenlin Baizhu Powder (P<0.05).The rat model of ulcerative colitis with syndrome of spleen deficiency and dampness stagnancy is successfully induced and has the characteristics of ulcerative colitis of humans both in pathological changes and in syndrome.