p38丝裂原活化蛋白激酶信号转导通路在诱导Barrett食管发生中的作用

The rule of p38 signal transduction pathway in the pathogenesis of Barrett esophagus

目的探讨脱氧胆酸在Barrett食管发生中的作用。方法用无血清的角朊细胞培养基体外培养人正常食管黏膜上皮细胞，应用不同浓度的脱氧胆酸及p38丝裂原活化蛋白激酶特异抑制剂SB203580干预细胞培养，用Western印迹法检测总p38、磷酸化p38和同源异型框转录因子（CDX2）蛋白的表达变化，评估磷酸化p38和CDX2表达变化的相关性。多组均数比较采用单因素方差分析，两两比较采用LSD法。结果Western印迹分析显示，培养24h后与对照组（磷酸化p38为13．7％±1.0％、CDX2蛋白为0）相比，随着脱氧胆酸浓度的逐渐增高，磷酸化p38的水平和CDX2蛋白的表达量逐渐增多，在500umol／L时均达最高水平（分别为44．0％±1．7％和8．59±1．25），差异有统计学意义（P〈0．05）。应用SB203580预处理2h后，再用含500umol／L脱氧胆酸的培养基培养24h，磷酸化p38的水平（28．3％±2．2％）和CDX2蛋白的表达量（0．94±0．13）较脱氧胆酸组（分别为50．5％±9．5％和2．31±0．41）均下降。结论脱氧胆酸可以诱导人正常食管黏膜上皮细胞CDX2表达，且与p38的活化有关，p38的磷酸化激活可能参与了Barrett食管的发生。

Objective To investigate the role of deoxycholic acid （DCA） in the pathogenesis of Barrett esophagus. Methods Normal human esophageal mucosal epithelial cells were cultured in vitro with defined keratinocyte serum-free media （D-KSFM）. The cultured cells were treated with different concentrations of DCA and specific p38 mitogen activated protein kinase （MAPK） inhibitor. The expression of p38, phosphorylated p38 （p-p38） and caudal-related homeodomain transcription 2 （CDX2） at protein level were assessed by Western blot. The correlation between p-p38 and CDX2 was analyzed. The data were analyzed by one way ANOVA and LSD test. Results After being cultured with DCA for 24 h, the expression of p-p38 and CDX2 increased along with the increasing of DCA concentration. Compared with the control group （p-p38 was 13.7%± 1.0% and CDX2 protein was 0）, the difference was statistically significant （P〈 0. 05）. When DCA was at 500 μmol/I., the expression of p-p38 and CDX2 reached the highest level （44.0% ± 1.7% and 8.59± 1.25）. After pretreated with SB203580 for two hours and then 500 /~mol/L DCA was added into cell culture, both expression level of p-p38 and CDX2 decreased compared with 500μmol/L DCA group （p-p38：28.3±2.2% vs50.5%±9.5%, CDX2：0.94±0.13 vs 2.31±0.41） after 24 h. Conclusions DCA can induce the expression o{ CDX2 in normal human esophageal mucosal epithelial cells, which is related with the activation of p38. The phosphorylation of p38 maybe involved in the pathogenesis of Barrett esophagus.