Ladage Patrick M, Jester James V, Petroll W Matthew, Bergmanson Jan P G, Cavanagh H Dwight
Department of Ophthalmology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75039-9057, USA.
Invest Ophthalmol Vis Sci. 2003 Mar;44(3):1056-63. doi: 10.1167/iovs.02-0725.
To study the effects of extended contact lens wear (EW) on the movement of basal epithelial cells toward the corneal surface.
Rabbits (n = 32) were injected with 5-bromo-2-deoxyuridine (BrdU) to label a group of proliferating basal epithelial cells, and, 24 hours later, one randomly chosen eye was fitted with a low- or medium-oxygen-transmissible (Dk/t) rigid gas permeable (RGP) contact lens, while the other eye served as the control (n = 28). Four rabbits were not fitted with any contact lens. Rabbits were euthanatized at different time points and the corneal epithelium was immunocytochemically stained for BrdU and/or Ki-67 and counterstained with propidium iodide or Syto 59. Corneal flatmount tissues were examined three dimensionally under a laser confocal microscope and the location of each BrdU-labeled cell in the corneal epithelium (basal or suprabasal) was determined.
Four days after injection of BrdU, both low- (P < 0.001) and medium-Dk/t RGP (P < 0.001) lens groups showed significantly more BrdU-labeled cells in the basal cell layer than in the control eyes. Six days after injection of BrdU, a small percentage of BrdU-labeled cells (<0.5%) were Ki-67 positive.
Within 6 days, the majority (80%) of BrdU-labeled basal cells became terminally differentiated and rarely divided secondarily in the central epithelium. Short-term use of low- and medium-Dk/t RGP EW contact lenses slows the normal movement of basal epithelial cells toward the surface in the central cornea. This is consistent with known EW-lens-induced decreases in corneal epithelial basal cell proliferation and surface cell exfoliation. Overall, the data suggest that EW lenses significantly inhibit the normal homeostatic turnover rate of the corneal epithelium.
研究长时间佩戴隐形眼镜（EW）对基底上皮细胞向角膜表面移动的影响。
给32只兔子注射5-溴-2-脱氧尿苷（BrdU）以标记一组增殖的基底上皮细胞，24小时后，随机选择一只眼睛佩戴低氧或中氧透过率（Dk/t）的硬性透气性（RGP）隐形眼镜，另一只眼睛作为对照（n = 28）。4只兔子未佩戴任何隐形眼镜。在不同时间点对兔子实施安乐死，对角膜上皮进行免疫细胞化学染色以检测BrdU和/或Ki-67，并使用碘化丙啶或Syto 59进行复染。在激光共聚焦显微镜下对角膜平铺组织进行三维检查，并确定每个BrdU标记细胞在角膜上皮（基底或基底上层）中的位置。
注射BrdU四天后，低Dk/t（P < 0.001）和中Dk/t RGP（P < 0.001）镜片组的基底细胞层中BrdU标记的细胞明显多于对照眼。注射BrdU六天后，一小部分BrdU标记的细胞（<0.5%）为Ki-67阳性。
在6天内，大多数（80%）BrdU标记的基底细胞终末分化，在中央上皮中很少再次分裂。短期使用低Dk/t和中Dk/t RGP EW隐形眼镜会减缓基底上皮细胞在中央角膜向表面的正常移动。这与已知的EW镜片引起的角膜上皮基底细胞增殖和表面细胞脱落减少一致。总体而言，数据表明EW镜片显著抑制角膜上皮的正常稳态更新率。
