亚硝胺致食管癌前病变时Wnt通路抑制因子的变化及膈下逐瘀汤的影响

Changes in Wnt pathway inhibiting factors in nitrosamine-induced esophageal precancerosis lesions and effect of Gexia Zhuyu decoction

目的:探讨甲基苄基亚硝胺(MBNA)诱发食管癌前病变Wnt通路抑制因子的变化及膈下逐瘀汤的影响。方法:Wistar大鼠按3.5 mg·kg-1体重剂量皮下注射MBNA溶液,每周2次,造模首日起以膈下逐瘀汤16,8 g·kg-1剂量灌胃给药,于造模第10周处死各组大鼠,观察食管黏膜病理变化,荧光定量PCR检测sFRP1,sFRP4,Axin1,Axin2,GSK-3βmRNA转录水平,Western blot检测β-catenin蛋白水平。结果:MBNA诱导下,模型组大鼠食管黏膜病理学检查呈轻度不典型增生,膈下逐瘀汤高、低剂量组与模型组比较病理形态学与组织学均未有明显改善;模型组大鼠食管组织sFRP1,sFRP4,Axin1,Axin2基因转录水平较对照组降低(P<0.05或P<0.01),β-catenin蛋白水平较对照组升高(P<0.01),膈下逐瘀汤低剂量组sFRP4,Axin1,Axin2基因转录水平较模型组升高(P<0.05或P<0.01),β-catenin蛋白水平较模型组降低(P<0.01)。结论:上调β-catenin蛋白水平、下调Wnt通路抑制因子转录水平从而增强Wnt通路活性是MBNA致大鼠食管癌前病变的可能分子机制之一,膈下逐瘀汤虽可下调β-catenin蛋白水平、上调Wnt通路抑制因子转录水平,但不足以阻断MBNA诱发的食管癌前病变。

Objective： To discuss the changes in Wnt pathway inhibiting factors in esophageal precancerosis lesions induced by methyl benzyl nitrosamine（ MBNA） and the effect of Gexia Zhuyu decoction. Method： Wistar rats were subcutaneously injected with MBNA（ 3. 5 mg·kg- 1） for twice per week to establish the model. Since the 1stday after the model establishment,they were orally administered with Gexia Zhuyu decoction（ 16,8 mg·kg- 1）. At the10 thweek,esophageal tissues were collected to observe the pathological changes of esophageal mucosa,detect SFRP1,sFRP4,Axin1,Axin2 and GSK-3β mRNA levels by fluorescent quantitation PCR analysis and β-catenin protein level by Western blotting. Result： Being induced by MBNA,rats in the model group showed slight atypical hyperplasia in the histopathological examination. Compared with the normal group,Gexia Zhuyu decoction dose high and low groups showed no significant pathomorphological and histological changes. The model group showed lower gene transcription levels of esophageal tissues sFRP1,sFRP4,Axin1 and Axin2（ P 〈 0. 05 or P 〈 0. 01） and higher β-catenin protein expression level（ P 〈0. 01） than the normal control group. The Gexia Zhuyu decoction low dose group showed higher gene transcription levels of esophageal tissues sFRP1,sFRP4,Axin1 and Axin2（ P 〈 0. 05 or P 〈 0. 01） and lower β-catenin protein expression level（ P 〈 0. 01） than the normal control group. Conclusion： Up-regulated β-catenin protein level and down-regulated Wnt pathway could enhance Wnt pathway activity of MBNA-induced esophageal precancerous lesions. Gexia Zhuyu decoction could down-regulate the β-catenin protein level and up-regulate the transcription level of Wnt pathway inhibiting factors,but could not block MBNA-induced esophageal precancerosis lesions.