Effect Of Compound Glycyrrhizin On Intestinal Inlfammation In Expeirmental Ulcerative Colitis Of Rats

ObjectivesUlcerative colitis （ulcerative colitis, UC）,a kind ofinflammatory bowel disease （inflammatory bowel disease, IBD）, ischronic non-specific inflammatory lesions of the rectum and colonand the reason is remain unclear at present. Traditional UC drugs,such as aminosalicylate preparations, glucocorticoids andimmunosuppressants, etc, can control the symptoms of most patients,but after long-term use，the side effects are relatively big, forexample, patients after long-term use of sulfasalazine （SASP） willsuffer abdominal pain, headache, nausea and other adverse reactions,which are so unbearable for patients that SASP is not allowed touse at large doses. Although the side effect of the5-amino acidpreparations has been improved to some extent, due to the longercourse of UC treatment and higher price to afford, slower effectand greater toxicity of immunosuppressant, its clinicalapplication is also limited; glucocorticoid, the rapidly-effective drug of induction and remission in UC acute phase, hasanti-inflammatory and immunosuppressive effect and better efficacyof short-term use, but after long-term use it may cause seriousadverse reactions, and can not shorten the course of the disease.Therefore, in recent years, people have been actively looking foreffective, safe, cheap, and less side effects of treatment of UCdrugs. Licorice, the active ingredient of compound glycyrrhizinacid and the main biologically active component of the Chineseherbal medicine licorice extract, has extensive pharmacologicalproperties of the anti-inflammatory, anti-ulcer, anti-allergy,detoxification, anti-oxidation, anti-tumor, anti-virus, which ischaracterized by good efficacy and few adverse reactions,especially no side effects of hormone-like. At present, domesticand foreign research is focused on the compound glycyrrhizintreatment of hepatitis, but reports are rarely on its treatment ofUC.Methods40adult Sprague-Dawley （SD） rats （n=10） are randomly dividedinto four groups: normal control group received no treatment, theremaining three groups are prepared to ulcerative colitis modelwith2.5%sodium nitrobenzene/ethanol solution enema. The generalsituation of the rats after model establishment，each group bodyweight and colon tissue CMDI rated were observed to determinewhether the models were made successfully or not. Rats in Modelgroup are killed after3days when they are processed with salineenema. Rats in compound glycyrrhizin treatment group are dailytreated with40mg kg^-1 d^-1 compound glycyrrhizin solution enema, and after7days they are killed;7days later after the ratsin sulfasalazine （SASP） treatment group are daily processed with0.5g kg^-1) d^-1 SASP solution enema, they were killed. Afterdifferent processing and treatment, interleukin-4（IL-4）,interleukin^<sup>-17(IL^-17) expression levels in rat serum are detectedwith enzyme-linked immunosorbent assay.The experimental data, processed by SPSS17.0statisticalsoftware are expressed as mean±standard deviation（x±s）`. Thecomparison of group mean is applied with ONE-WAY ANOVA and q testis used for pairwise comparisons. P <0.05for the difference isstatistically significant.Results1. After enema treatment, compared with model group, rats incompound glycyrrhizin treatment group and SASP group, have lessdegree of diarrhea, shorter duration and better conditions ofmental status, anorexia, lazy move and coat gloss; each groupphysique after processed has increased significantly （P<0.05）; therat constitution in two treated groups are higher than the modelgroup and the control group （P<0.05）.2. In Model group, serum IL-4is obviously lower than in normalgroup, but IL^-17is much higher than the normal group （P<0.05）, IL-4is significantly increased after treatment by the compoundglycyrrhizin and the SASP treatment, IL^-17significantly reduced.The difference between compound glycyrrhizin treatment group andSASP group is no statistical significance.3.The normal control group NF-κB p65weakly expression, the model group colon tissue NF-kB p65expression was significantlyhigher than the control group （P <0.05）; two treatment groups colontissue NF-kappaB p65was significantly higher than the modelcontrol group, compared to colon tissue NF-kappaB p65expressionbetween the two treatment groups was statistically significant（P<0.05）, The difference between compound glycyrrhizin treatmentgroup and SASP group is no statistical significance.ConclusionsThe phenomenon that in the serum of rats with treatment ofCompound Glycyrrhizin, the level of IL-4increased and the IL-17level decreased significantly, shows that the compoundglycyrrhizin can promote the anti-inflammatory cytokines IL-4secretion and release, inhibit the pro-inflammatory cytokinesIL-17secretion and release, consequently it plays ananti-inflammatory effect.Licorice, the active ingredient of compound glycyrrhizin acidand the main biologically active component of the Chinese herbalmedicine licorice extract, has similar chemical structure withcorticosteroids, the possible treatment mechanism of UC is that therole of anti-inflammatory and anti-allergic is achieved by meansof mediation of cytokine function，correcting the imbalance ofTh1/Th2proportion，down-regulation of the synthesis of Th17cellswhich secrete IL-17and regulation of the strong cellular andhumoral immune.