西红花酸对溃疡性结肠炎大鼠模型的作用及其机制研究

目的: 研究西红花酸(crocetin)对2,4,6-三硝基苯磺酸(TNBS)/乙醇诱导的大鼠溃疡性结肠炎(ulcerative colitis, UC)的作用及可能机制。方法: 采用TNBS/乙醇混合复制溃疡性结肠炎模型,用不同剂量的西红花酸进行干预。观察大鼠结肠组织形态变化;检测髓过氧化物酶(MPO)、丙二醛(MDA)和超氧化物歧化酶(SOD)活性;ELISA法测定肿瘤坏死因子-α(TNF-α)和白介素-1β(IL-1β)含量;实时荧光定量PCR(Q-PCR)检测Toll样受体4(TLR4)和核转录因子-κBp65(NF-κBp65)基因的表达;免疫组化分析TLR4和NF-κBp65蛋白的表达。结果: 西红花酸能改善UC大鼠结肠形态及组织病理学变化;西红花酸能抑制MPO活性、降低MDA含量、提高SOD活性;西红花酸能下调TNF-α和IL-1β的含量;西红花酸能降低TLR4和NF-κBp65基因与蛋白的表达。结论: 西红花酸能有效改善溃疡性结肠炎大鼠的结肠炎症反应, 其作用机制与抗氧化、抑制TLR4/NF-κB信号通路等有关。

Effects of crocetin on ulcerative colitis in rats and the mechanism

AIM: To determine the effect of crocetin on ulcerative colitis(UC)induced by tri-nitrobenzene sulfonic acid(TNBS)in rats, and to explore the possible mechanism.METHODS: UC was induced by TNBS and ethanol in rats. After crocetin was given orally, the colon mucosa damage idex and histopathological score were determined, and the levels of MPO,MDA and SOD were measured. Tumor necrosis factor-α(TNF-α) and Interleukin-1β(IL-1β) in colon were detected by enzyme-linked immunosorbent assay(ELISA). Toll-like receptor4(TLR4) mRNA and nuclear factor-κBp65(NF-κBp65) mRNA expression were examined by Q-PCR. Immunohistochemistry staining was used to observe the expression of TLR4 and NF-κBp65.RESULTS: Crocetin greatly attenuated the severity of colonic gross lesions and reduced the histopathological scores. MPO activity and MDA concentration in colon were significantly increased,SOD activity was reduced in UC rats.Crocetin ameliorated these changes. Crocetin reduced the levels of TNF-α and IL-1β in colon. The expression of TLR4 and NF-κBp65 in colon were attenuated by crocetin.CONCLUSION: Crocetin can effectively attenuate the inflammatory reaction in UC rats,which may be due to the antioxidation and the inhibition of TLR4/NF-κB signal pathway.