Effect Of Natural Flavonoid Icaritin On Ulcerative Uolitis By Regulating Macrophage Function

Objective: As a traditional Chinese medicine,Epimedium has a variety of biological activities such as anti-inflammatory,anti-tumor,anti-oxidation,anti-virus and immunomodulatory activity.In this study,the effects of Epimedium on the expression of NO,interleukin-6(IL-6)and nuclear factor kappa B(NF-κB)in LPS-stimulated RAW264.7 cells were studied.In addition,DSS induced mouse ulcerative colitis model was established to evaluate the effects of icaritin on the pathophysiology and therapy of ulcerative colitis.At the same time,pathogenic mechanism of ulcerative colitis was researched by using this animal model.Methods:1 Cell culture,passage and seeding.2 After inoculation,the RAW264.7 cells were divided into control group,LPS-stimulated groups and icaritin-treated groups(5 μmol/L、10 μmol/L、20μmol/L).3 The effects of different concentrations of icariin(5 μmol / L,10 μmol /L,20 μmol/L)on NO and IL-6 in the cell model were detected and the changes of the protein expression of NF-κB were analyzed before and after the intervention with icaritin.4 The effects of Epimedium on the disease activity index,length of rat colon and paraffin section of colon were analyzed by intervention with different doses(5mg/kg/d、10mg/kg/d、20mg/kg/d)of icaritin in the DDS induced mouse ulcerative colitis animal model.At the same time,the changes of NO,IL-6 and NF-κB in colonic tissue were analyzed.Results:1 In LPS-stimulated RAW264.7 cells,the activation of NO and IL-6 in the icariin-treated groups were significantly inhibited and the expressions ofNF-κB were also decreased.Icaritin inhibited NO,IL-6,NF-κB in a concentration-dependent manner.NO,IL-6 and NF-κB decreased significantly,as the concentration of icaritin increases.2 In DDS-induced ulcerative colitis,the disease activity index in mice decreased significantly after the intervention of icariin,5mg / kg / d icariin treatment group showed no significant improvement compared with the control group,but the 10 mg / kg / d and 20 mg / kg / d icariin treatment groups showed a significant disease activity index inhibition.The length of the colon in mice also recovered after icariin treatment,but there was no statistical significant in the recovery degree.Icaritin significantly reduced the inflammatory cell infiltration,inhibited the formation of ulcers and promoted the recovery of colon crypt morphology and the degree of colon tissue pathology improved with the increase of icaritin intervention dose which showed in a dose-dependent manner.NO,IL-6 and NF-κB in icaritin intervention group were significantly decreased in colonic tissues of mice,and the decreased degree was also dose-dependently related to icaritin intervention.Conclusion:Through this experiment we draw the following conclusions:1 Icariin inhibited the occurrence and development of ulcerative colitis.2 The mechanism of icariin caused imrovement of ulcerative colitis is related to decreased immune response level by inhibiting the NF-κB signaling pathway and down-regulating NO and IL-6.