RBCD患者角膜上皮细胞的凋亡

目的观察Reis Bücklers角膜营养不良（RBCD）中角膜上皮细胞的凋亡现象，探讨凋亡在RBCD发病机制中可能的作用。方法2家系中4例RBCD患者(经基因检测均明确为TGFB I基因R124L突变)，取其板层或穿透性角膜移植术后的病变角膜，HE及特殊染色后行光学显微镜观察；超薄切片后行透射电子显微镜观察超微结构；采用脱氧核糖核苷酸末端转移酶介导的缺口末端标记法（TUNEL）检测病变角膜中凋亡细胞的表达。以4例正常角膜组织标本为对照。结果RBCD患者角膜上皮细胞微绒毛减少或消失，基底细胞间有小块高电子密度物质，基底细胞出现凋亡现象，前弹力层及前部基质中可见大量棒状高电子密度沉淀物。TUNEL染色发现角膜上皮基底细胞层凋亡细胞，凋亡细胞阳性率为（15.02±3.09）%，显著高于正常对照角膜（P＜0.01）。结论RBCD患者存在角膜上皮基底细胞凋亡，可能是造成角膜前弹力层异常沉淀及其临床症状的原因之一。

Apoptosis of corneal epithelium in Reis Bücklers corneal dystrophies

To observe the apoptosis of corneal epithelium in Reis Bücklers corneal dystrophies (RBCD), and to explore the role of apoptosis in the pathogenesis of Reis Bücklers corneal dystrophies. MethodsCornea buttons were obtained from 4 RBCD patients (with R124L mutation of TGFBI gene) in 2 pedigrees who underwent lamella or penetrating keratoplasty. Sections with HE and special staining were observed by light microscopy. Ultra thin sections were performed and ultrastructure changes were investigated under a transmission electron microscope. Terminal deoxynucleotidyl transferase mediated nick end labeling (TUNEL) staining technique was used to examine the apoptosis of the cornea. Four normal cornea specimens served as controls. ResultsIn the RBCD cornea epithelium, microvilli were decreased or lost. Small clumps of deposits with a high electron density were found between basal cells. Some basal cells had apoptotic signs. A great quantity of rod shape deposits was seen in the Bowman′s layer and the anterior part of the stroma. Apoptosis was found in the corneal basal epithelium by TUNEL staining with a positive rate of（15.02±3.09）%. There was a significant difference between RBCD and normal cornea（P＜0.01）. ConclusionApoptosis of corneal basal epithelium in RBCD patients may be one of the reasons for abnormal deposit in the Desement membrane and clinical symptoms.