The Effects Of LPS/KN62Pretreatment On Colitis Of BALB/C Mice Animal Model Induced By Trinitrobenzene Sulfonic Acid

Objective:To explore the effects of Lipopolysaccharide(LPS)/inhibitor of calcium/calm-odulin-dependent protein kinaseII (KN62) pretreatment on colitis of BALB/C miceanimal model induced by trinitrobenzene sulfonic acid and detect the expression ofIL-6mRNA in the intestinal mucosa, the expression level of Mouse MHC-II molecu-les in the Lamina propria.Methods:Forty female BALB/C mice which were fasted but drunk water for24hoursbefore the experiment, were randomly assigned to four groups and each group had10of them: normal control group(NC group), model control group(UC group), LPSgroup and KN62group. Except that the normal control group was administeredintracolonically with saline, the other groups were administered intracolonically withTrinitrobenzene sulfonic acid ethanol solution(100mg/kg) to construct colitismodel.Two hours before the beginning of coloclyster, mice of the LPS group alsoreceived intraperitoneal injection of Lipopolysaccharide, KN62group receivedintraperitoneal injection of KN62,while the model control group receivedintraperitoneal injection of saline. All animals were sacrificed on day7aftertreatment. The disease activity index(DAI)and histological index(HI) were calculated,the expression of IL-6mRNA in the intestinal mucosa was measured by reversetranscription Polymerase Chain Response(RT-PCR), the expression level of MouseMHC-II molecules in the Lamina propria. was measured by Flow cytometry.Results:On day7after treatment, DAI in all groups (in order of NC,LPS,KN62,UCgroup) respectively is0,10.68±1.16,4.36±0.52,8.75±0.91; histological index(HI) is1.80±0.58,13.54±1.12,5.47±0.81,10.92±0.93; the expression of IL-6mRNAmeasured by RT-PCR is0.14±0.12,0.71±0.25,0.38±0.13,0.53±0.21; MHC-IImeasured by Flow cytometry is1.26±0.11,7.32±0.14,2.38±0.16,4.97±0.23.From the results we can find that the DAI score, HI score, the expression of IL-6mRNA,thelevel of MHC-II with NC group compared with UC group had statistical difference(P<0.05),LPS group compared with UC group had statistical difference(P<0.05),KN62group compared with UC group had statistical difference(P<0.05).Conclusion:1.From the comprehensive comparison of the performance between NC groupand UC group, we can find that TNBS in50%ethanol enemas(100mg/kg) can inducethe better animal model for research.2.After treatment with LPS(5mg/kg), DAI,HI,the expression of IL-6mRNA inthe intestinal mucosa and the expression level of Mouse MHC-II molecules in theLamina propria of mice with experimental colitis increased indicates LPS can amplifythe inflammation.3.After treatment with KN62(25ng/mouse), DAI,HI,the expression ofIL-6mRNA in the intestinal mucosa and the expression level of Mouse MHC-IImolecules in the Lamina propria of mice with experimental colitis decreased indicatesKN62can attenuate the inflammation and be useful for protection to host.