Yamamoto Nobutaka, Yamamoto Naoka, Jester James V, Petroll W Matthew, Cavanagh H Dwight
Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, 75039-9057, USA.
Eye Contact Lens. 2006 May;32(3):114-20. doi: 10.1097/01.icl.0000177384.27778.4c.
To investigate the effects of hypoxia on lipid raft formation and Pseudomonas aeruginosa internalization by the corneal epithelium with and without the physical effects of contact lens wear.
One eye of each rabbit was randomly fitted with a low-Dk rigid gas-permeable contact lens (LDCTL) or closed with sutures, with the other as a control. After 1 day or 3 days, the rabbits were killed and bacterial invasion was assessed by gentamicin survival assay. Lipid rafts were identified by staining with FITC-conjugated beta subunit of cholera toxin. Corneal epithelial Bcl-2 expression was detected by Western blotting; surface epithelial cell size and thickness (epithelium and stroma) were measured by confocal microscopy.
One-day hypoxia induced no significant changes in P. aeruginosa internalization, Bcl-2 expression, or lipid raft formation except in one of four eyelid-closed eyes. After 3 days, P. aeruginosa internalization was increased significantly (P < 0.05) in LDCTL-wearing eyes and not significantly (P = 0.10) increased in eyelid-closed eyes. Both 3-day test conditions also induced lipid raft-forming cells that bound P. aeruginosa, albeit in different regions of the cornea (peripherally in LDCTL-wearing eyes and centrally in closed eyes); did not alter epithelial thickness or surface cell size; and appeared to decrease epithelial Bcl-2 expression.
This is the first direct comparison in vivo between two different methods inducing hypoxia on the corneal surface. Association of P. aeruginosa internalization with lipid raft formation in both conditions suggests a critical link among prolonged hypoxia, lipid raft formation, and susceptibility to P. aeruginosa infection. However, different distribution patterns of lipid raft-forming cells suggest physical effects of contact lens wear may direct localization of lipid raft-associated P. aeruginosa internalization on the corneal surface.
研究缺氧对角膜上皮脂质筏形成及铜绿假单胞菌内化的影响，以及佩戴隐形眼镜的物理作用对此的影响。
将每只兔子的一只眼睛随机佩戴低透氧性硬性透气性隐形眼镜（LDCTL）或缝合闭合，另一只眼睛作为对照。1天或3天后，处死兔子，通过庆大霉素存活试验评估细菌侵袭情况。用荧光素异硫氰酸酯（FITC）偶联的霍乱毒素β亚基染色鉴定脂质筏。通过蛋白质免疫印迹法检测角膜上皮Bcl-2表达；用共聚焦显微镜测量表面上皮细胞大小和厚度（上皮和基质）。
除四只缝合闭合眼睛中的一只外，1天的缺氧对铜绿假单胞菌内化、Bcl-2表达或脂质筏形成无显著影响。3天后，佩戴LDCTL的眼睛中铜绿假单胞菌内化显著增加（P<0.05），而缝合闭合眼睛中无显著增加（P=0.10）。两种3天的试验条件均诱导了结合铜绿假单胞菌的脂质筏形成细胞，尽管在角膜的不同区域（佩戴LDCTL的眼睛中在周边，缝合闭合眼睛中在中央）；未改变上皮厚度或表面细胞大小；且似乎降低了上皮Bcl-2表达。
这是首次在体内对两种不同的角膜表面缺氧诱导方法进行直接比较。在两种情况下，铜绿假单胞菌内化与脂质筏形成的关联表明长期缺氧、脂质筏形成和对铜绿假单胞菌感染的易感性之间存在关键联系。然而，脂质筏形成细胞的不同分布模式表明，佩戴隐形眼镜的物理作用可能指导脂质筏相关的铜绿假单胞菌内化在角膜表面的定位。
