Objective: To study the expression levels of glial cell line-derived neurotrophic factor family receptor α-1 (GFRα1) and enhancer of zeste homolog 2 (EZH2) in the intestinal tissue of children with Hirschsprung's disease (HSCR), as well as the role of EZH2 in the regulation of GFRα1 gene expression and the pathogenesis of HSCR.
Methods: The samples of colon tissue with spasm from 24 children with HSCR after radical treatment of HSCR were selected as the experimental group, and the samples of necrotized colon tissue from 18 children with neonatal necrotizing enterocolitis after surgical resection were selected as the control group. Real-time PCR and Western blot were used to measure the expression levels of GFRα1 and EZH2 in colon tissue in both groups. Human neuroblastoma SH-SY5Y cells were divided into an EZH2 over-expression group and a negative control group. The cells in the EZH2 over-expression group were transfected with pCMV6-EZH2 plasmid, and those in the negative control group were transfected with pCMV6 plasmid. The expression levels of EZH2 and GFRα1 were measured after transfection.
Results: Compared with the control group, the experimental group had significant reductions in the mRNA and protein expression levels of GFRα1 and EZH2 in colon tissue (P<0.05), and the protein expression of EZH2 was positively correlated with that of GFRα1 (r=0.606, P=0.002). Compared with the negative control group, the EZH2 over-expression group had significant increases in the expression levels of EZH2 and GFRα1 after SH-SY5Y cells were transfected with EZH2 over-expression plasmid (P<0.05).
Conclusions: Low expression of EZH2 in the colon tissue of children with HSCR may be one of the causes of inadequate expression of GFRα1 and onset of HSCR.
目的: 通过检测先天性巨结肠（HSCR）患儿结肠组织内胶质细胞源性神经营养因子受体α1（GFRα1）及果蝇Zeste基因增强子人类同源物2（EZH2）的表达水平，探讨EZH2在调控GFRα1基因表达及HSCR发病过程中的作用。
方法: 随机选取24例行巨结肠根治术的HSCR患儿，取痉挛段结肠组织为试验组。以同期18例因新生儿坏死性小肠结肠炎而接受手术治疗的患儿，取手术切除的坏死结肠组织作为对照组。利用实时荧光定量PCR及Western blot检测两组结肠组织内GFRα1、EZH2的表达水平。将人神经母细胞瘤细胞SHSY5Y分为EZH2过表达组和阴性对照组，EZH2过表达组转染pCMV6-EZH2质粒，阴性对照组转染pCMV6质粒，检测转染后细胞中GFRα1、EZH2的表达水平。
结果: 与对照组相比，试验组GFRα1及EZH2 mRNA和蛋白的表达水平降低（P < 0.05），且EZH2蛋白表达水平与GFRα1蛋白呈正相关（r=0.606，P=0.002）。与阴性对照组相比，EZH2过表达组EZH2及GFRα1表达水平明显上调（P < 0.05）。
结论: HSCR患儿结肠组织中EZH2低表达可能是GFRα1表达不足，诱发HSCR的原因之一。