翼状胬肉组织中ATP结合盒转运蛋白B5的表达变化及意义

Expression changes and significance of ATP-binding cassette transporter B5 in pterygium

背景角膜缘干细胞（LSCs）缺乏可引起多种眼表疾病，如翼状胬肉等。ATP结合盒转运蛋白B5（ABCB5）是新发现的特异性LSCs标志物，研究ABCB5在翼状胬肉组织中的表达变化对于翼状胬肉的防治具有重要的临床意义。目的研究ABCB5在翼状胬肉组织中的表达变化，探讨其在翼状胬肉发生和发展中的作用。方法收集2015年1-11月在解放军474医院行原发性翼状胬肉切除术的手术标本37例，同期收集年龄匹配的行斜视矫正术和视网膜脱离复位术患者的正常结膜组织22例。采用免疫组织化学法检测ABCB5在翼状胬肉组织标本中的表达和定位，分别采用Westernblot和实时荧光定量PCR法检测翼状胬肉标本中ABCB5蛋白及其mRNA的相对表达量，并与正常结膜标本进行比较。结果ABCB5蛋白表达于所有22例正常结膜复层扁平细胞的细胞质和细胞核中，以基底层细胞中表达更为明显，呈现明显极性。在37例翼状胬肉标本中，可见ABCB5阳性表达者34例，占91．89％，ABCB5表达阴性者3例，占8．11％。正常结膜组和翼状胬肉组ABCB5蛋白相对表达量分别为0．90±0．31和0．59±0．41，ABCB5mRNA表达量分别为1．01±0．26和0．65±0．32，翼状胬肉组ABCB5蛋白和mRNA的相对表达量均明显低于正常结膜组，差异均有统计学意义（t=-0．266，P=0．011；t=-4．560，P=0．000）。结论LSCs标志物ABCB5的表达下调提示LSCs的减少和缺失与翼状胬肉的发生和发展有关，提示ABCB5检测可能作为翼状胬肉发生和发展、术后复发及疗效评估的观察指标之一，也可能成为翼状胬肉的治疗靶点。

Background Limbal stem cells （LSCs） deficiency leads to many ocular surface diseases, such as pterygium and so on. ATP-binding cassette transporter B5 （ABCB5） is a recently discovered marker of LSCs. Understanding the expression changes of ABCB5 in pterygium tissue has an important clinical significance for pterygium. Objective This study was to investigate the expression changes of ABCB5 in pterygium tissue. Methods Thirty-seven pterygium tissue specimens were collected from primary pterygium patients who received pterygium surgery,and 22 normal conjunctival tissue specimens were obtained from the strabismus patients and retinal detachment patients during surgery in 474 Hospital of Chinese PLA from January 2015 to November 2015. Immunochemistry was employed to detect the expression and location of ABCB5 in the specimens, and the protein and mRNA expressions of ABCB5 were detected by Western blot and real-time fluorescence quantitative PCR, respectively. The results were compared between normal conjunctival tissues and pterygium tissue. Results ABCB5 protein was expressed in the cytoplasm and nuclei of stratified squamous epithelium of 22 normal counjunctival tissue specimens,especially in the basal layer cells,and showed obvious polarity in normal conjunctiva. In pterygium group,ABCB5 protein was positively expressed in 91.89% specimens （34/37） and the expression was absent in 8.11% specimens （3/37）. The relative expression levels of ABCB5 protein were 0.90±0. 31 and 0. 59±0. 41, and those of ABCB5 mRNA were 1.01±0.26 and 0. 65±0. 32 in the normal conjunctival tissues and pterygium tissue, respectively, showing significant differences between them （ protein ： t = -0. 266, P = 0.011 ; mRNA ： t = -4. 560, P=0. 000）. Conclusions Down-regulation of ABCB5 in pterygium indicates the decreasing and losing of LSCs, which may play an important role in the development of pterygium. ABCB5 may be a useful indicator for the prediction of development and recurrence of pterygium and has an important implication for treating evaluation,and it may also be a target for the management of pterygium.