家兔角膜准分子激光切削术后病理学观察

A Histopathologic Study of Rabbit Cornea after Excimer Laser Photorefractive Keratectomy

目的对近期准分子激光角膜切削术（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ，ＰＲＫ）后角膜伤口变化进行组织病理学观察。方法应用１９３μｍ扫描式准分子激光对８只实验兔眼行光学角膜切削术并于术后２月时组织病理学检查。结果切削区角膜表面光滑，均匀一致，上皮轻度增厚；基底膜再生，但呈厚薄不一、不连续等不成熟表现，上皮和实质层仍存在散在裂隙；基质处大部分新生胶原纤维排列有序，但局部浅实质层可见角膜细胞增多等瘢痕样改变。结论兔眼ＰＲＫ术后２月显示，组织结构基本正常，但仍存有组织薄弱处和特殊性改变。强调半桥粒－基底膜复合体在ＰＲＫ上皮修复中的意义。

ObjectiveTo evaluate corneal healing response histopathologically after excimer laser photorefractive keratectomy (PRK) with scanning excimer laser.MethodsUsing NIDIK EC 5000,an argon fluoride scanning excimer laser system(193nm),the rabbit corneas were ablated at a depth of 80 90 μm and diameter of 5 6 mm of optical zone.We followed them up for up to 2 months with a slit lamp postoperatively and investigated them histologically and structurally at 2 months by light microscopy.ResultsAt 2 months,all showed some degree of haze by slit lamp microscopy.The ablated surface was observed to be smooth and uniform,and reepithelialization had occurred with epithelial thickening slightly.However,slight epithelial hyperplasia was observed at the margin of the ablation where more cell layers and increased cell numbers were expected.It may have benefited from transition zone ablation.The basement membrane was reestablished but discontinuities and duplication were seen in some areas;No infiltration was seen with inflammation.Different sizes of fissures could be seen between epithelium and stroma which may explain why epithelial defects occurred easily after PRK,such as epithelial abrasions.Most anterior stromata showed regular lamellar structures,some were scarred with an increase in number of fibrocytes.The stroma underlying the untreated area appeared normal.No endothelial damage was observed.ConclusionDespite recovery of a continuous and smooth epithelial layer and near normal corneal tissues 2 months after PRK,abnormalities of both epithelium and superficial stroma could be detected in the area of ablation.The role of the hemidesmosomes basement membrane complex in normal healing of the ablation was emphasized.