Effects Of Different Administration Approaches For Ulcerative Colitis Of Rat And It's Mechanism

PartⅠEstablishment of rat colitis model induced by TNBSObjective:develop a TNBS-induced model of colitis in rats which can inject drugs by a tube to colon for therapy of ulcerative colitisMaterials and Methods:Seventy-two SD rats were randomly divided into three groups: model, mock model and normal group (24 rats in each group).In the model and mock model group, a tube was inserted into the cecum of rat and fixed above the neck for injecting drugs, UC in the model group was induced by injecting TNBS (100mg/kg in 50% ethanol) by syringe after claping 2 cm tract of colon 6 cm far away from cecum.Feces, psychosis and appetite were observed, body weight were recorded daily.Rats were killed afterl,3,7 and 14 d, serum and the colons were isolated for the measurement of macroscopic, histologic, and biochemical parameters of colitis.Result:On the first day, tats in the model group had loose and bloody stools.and the symptoms lasted for about 8 days. Body weight were markedly decreased for 8-10 days. Obvious pathological changes in the colon were observed on third and seventh day, characterized by mucosal necrosis and transmutable inflammation,instead of a large number of lymphocyte infiltration, granulation tissue, and crypt abscess formation on fourteenth day.MPO activity and expression of Interleukin (IL)-1β,tumor necrosis factor (TNF)-α,and interleukin (IL)-6 peaked on 3 and 7 day, decreased on 14 day. In the mock model group, the rats had loose stools on first day, and recovered on second day.Conclusion:A new model of colitis was established in rats,.ulcerative size,inflammation severity and positive rate are more stable than traditional methods for better evaluation of treatment effect. Drug can be injected to the colitis tract,which may be useful to explore a better method for the treatment of UC in rats. PartⅡEffects of different administration approaches for ulcerative colitis of ratObjective To observe the effect of injecting 5-ASA by a tube from cecum to colon in rats model with ulcerative colitis comparison with oral 5-ASA or mesalazine(aidisha)Method 60 rats were devided into sham operation group,model group,injecting 5-ASA group,oral mesalazine group,oral 5-ASA group(12 rats in each group).The rats in sham operation group and model group were injected normal saline by tube(2ml,bid),the rats in injecting 5-ASA group were injected 5-ASA by tube(2ml,bid,100mg/kg), oral mesalazine group and oral 5-ASA group were given 5-ASA (2ml,bid,100mg/kg).body weight was recorded every day.After 7 days,blood in the heart of rats were got and blood serum of them were separated from the blood in every group, the colons were isolated for the measurement of macroscopic, histologic, and biochemical parameters of colitis.Result1 comparison with model group,score of colonic damage in injecting 5-ASA group and oral mesalazine group degraded obviously,the activity of MPO,scores of IHC,expression of IL-1β,IL-6,TNF-αmRNA in colon tissue,level of IL-1β,IL-6,TNF-αin serum decended obviously(p<0.05),which had no chang obviously in oral 5-ASA group(p>0.05).2 comparison with oral 5-ASA group, score of colonic damage in injecting 5-ASA group and oral mesalazine group degraded obviously,the activity of MPO,scores of IHC, expression of IL-1β,IL-6,TNF-αmRNA in colon tissue,level of IL-1β,IL-6,TNF-αin serum decended obviously(p<0.05).3 comparison with oral mesalazine group, score of colonic damage in injecting 5-ASA group degraded obvio(?)sly,the activity of MPO,scores of IHC, expression of IL-1β,IL-6,TNF-αmRNA in colon tissue,level of IL-1β,IL-6,TNF-αin serum decended obviously(p <0.05).Conclusion Injecting 5-ASA by a tube from cecum to colon is superior to oral 5-ASA or mcsalazinc for TNBS-induced rat ulcerative colitis PartⅢHPLC Determination of 5-Aminosalicylic Acid in Plasma colonic tissue and feces in ratObjective:HPLC was employed to the determination of the content of of 5 anfinosalicylic acid(5 ASA).Method:60 rats were devided into sham operation group,model group,injecting 5-ASA group,oral mesalazine group,oral 5-ASA group(5 rats in each group). The HPLC was adopted with a Nu-cleosil 100-5 C18 column.A mobile phase consisting of phosphate buffer-acetonitrile-tetrahydrofuran(85:10:5)was used with a flow rate of 0.9 mL/min, and the UV detection wavelength at 254 nm.After 5-ASA was derivatized to acetyl-5-ASA and the proteins were precipitated with trichloroacetic acid. the sample was directly injected to determine the content of 5-ASA in serum,colon and stool.Result:1. comparison with oral 5-ASA group,concentration of 5-ASA in serum of oral mesalazine group and injecting 5-ASA group degraded obviously at every time;comparison with oral mesalazine group, concentration of 5-ASA in serum of injecting 5-ASA group degraded obviously more at every time.2. comparison with oral 5-ASA group,concentration of 5-ASA in colonic tissue of oral mesalazine group and injecting 5-ASA group increased obviously at every time;comparison with oral mesalazine group, concentration of 5-ASA in colonic tissue of injecting 5-ASA group increased obviously more at every time.3. comparison with oral 5-ASA group,concentration of 5-ASA in feces of oral mesalazine group and injecting 5-ASA group increased obviously at every time;comparison with oral mesalazine group, concentration of 5-ASA in feces of injecting 5-ASA group increased obviously more at every time. Conclusion:comparison with oral 5-ASA group and oral mesalazine group, injecting 5-ASA to colon by tube maked concentration of 5-ASA degrade in serum,and increased concentration of 5-ASA in colonic tissue and feces of rat.Thus,this method play a more effective role for the treatment of ulcerative colitis in rats.