孕烷X受体/NF-κB信号通路在美沙拉嗪改善大鼠溃疡性结肠炎中的作用

目的研究孕烷X受体/NF-κB(PXR/NF-κB)信号通路在美沙拉嗪(Mes)干预溃疡性结肠炎(UC)大鼠中的作用。方法SPF级雄性SD大鼠一次性结肠灌注2,4,6-三硝基苯磺酸(TNBS)每只0.8 mL,连续4 d。每天观察各组大鼠体质量,粪便性状,计算病变活动指数(DAI),DAI为正常组的2倍以上,则为造模成功。模型大鼠按照分组每天分别ig给予Mes 300 mg·kg^-1(模型+Mes组)、利福平(Rif)50 mg·kg^-1+Mes组(模型+Mes+Rif组)和酮康唑(Ket)35 mg·kg^-1+Mes组(模型+Mes+Ket组),均先给Rif和Ket、给药4 d后给予Mes,连续7 d。HE染色观察结肠病理改变;ELISA法测定血浆肿瘤坏死因子α(TNF-α)、γ干扰素(IFN-γ)、白细胞介素4(IL-4)和IL-13含量;比色法检测结肠髓过氧化物酶(MPO)活性;实时PCR和Western印迹法检测结肠PXR,NF-κB,NF-κB p65和κB抑制因子α(IκB-α)蛋白和mRNA水平。结果模型组大鼠体质量明显下降,并伴有稀便和血便的症状。与UC模型组相比,模型+Mes组大鼠体质量明显升高(P<0.05),HE染色见结肠组织病变程度减轻;血浆TNF-α与IFN-γ含量、结肠组织中MPO活性、NF-κB mRNA及p-P65蛋白水平显著降低(P<0.05),而血浆IL-4和IL-13含量及结肠组织Pxr,NF-κB p65和IκB-αmRNA水平均显著升高(P<0.05)。与模型+Mes组相比,模型+Mes+Rif组结肠组织Pxr和NF-κB通路相关靶基因表达水平差异无统计学意义,而模型+Mes+Ket组结肠中Pxr和IκB-αmRNA水平显著下降(P<0.05)。结论Mes对UC的治疗效果很可能与激活PXR/NF-κB信号通路有关。

Role pregnane X receptor/NF-κB signaling pathway in improving ulcerative colitis in rats by mesalazine

OBJECTIVE To investigate the role of pregnane X receptor/NF-κB(PXR/NF-κB)signaling pathway in the intervention of rats with ulcerative colitis(UC)exercised by mesalazine(Mes).METHODS SPF male SD rats were induced by rectal adminitration of 2,4,6-trinitrobenzenesulfonic acid(TNBS)0.8 mL perrat colon once for 4 d.The body mass and fecal characteristics of rats in each group were observed daily for 4 consecutive days.A disease activity index(DAI)that was more than twice that of the normal group meant,the success of the model establishment.The model rats were given Mes 300 mg·kg^-1·d^-1(Mes group),rifampicin 50 mg·kg^-1·d^-1+Mes group(Rif+Mes group)and ketoconazole 35 mg·kg^-1·d^-1+Mes group(Ket+Mes group)respectively.Rif and Ket were given for 4 d before Mes was given for 7 d.HE staining was used to observe the pathological changes in the colon.The levels of plasma tumor necrosis factor-alpha(TNF-α),interferon gamma(IFN-γ),interleukin-4(IL-4)and interleukin-13(IL-13)were measured by ELISA.The activity of colon myeloperoxidase(MPO)was detected by colorimetry;while real-time PCR and Western blotting were used to detect PXR and NF-κB,NF-κB p65 and NF-κB inhibitorα(IκB-α)protein and mRNA levels in the colon.RESULTS The body mass of the model group was significantly decreased with the symptoms of sparse stool and bloody stool.Compared with UC model group,the body mass of model+Mes group increased significantly(P<0.05).HE staining showed that the activity of colonic pathological changes was reduced.The levels of plasma TNF-α and IFN-γ,colon MPO activity,NF-κB mRNA and p-P65 protein in colonic tissue were significantly decreased(P<0.05),while the levels of plasma IL-4 and IL-13,Pxr,NF-κB p65 and IκB-αprotein in colonic tissue were significantly increased(P<0.05).Compared with model+Mes group,the expressions of Pxr and NF-κB pathway related target genes in model+Mes+Rif group were not statistically significant,while the expressions of Pxr and IκB-αin model+Mes+Ket group decreased significantly(P<0.05).CONCLUSION The therapeutic effect of Mes against UC may be related to the activation of PXR/NF-κB signaling pathway.