Wormstone I M, Liu C S, Rakic J M, Marcantonio J M, Vrensen G F, Duncan G
School of Biological Sciences, University of East Auglia, Norwich, UK.
Invest Ophthalmol Vis Sci. 1997 Feb;38(2):396-404.
The ocular humors are relatively low in protein, yet cell growth in the human capsular bag still occurs after extracapsular cataract extraction (ECCE) surgery. This resilient growth gives rise to posterior capsule opacification (PCO) in a significant proportion (30%) of patients. This study compared the ability of human lens cells to proliferate in serum-supplemented and protein-free medium.
Sham cataract operations were performed on human donor eyes. The capsular bag was dissected free, pinned flat on a petri dish, and incubated in Eagle's minimal essential medium (EMEM) alone or in EMEM supplemented with 10% fetal calf serum. Observations were made by phase-contrast microscopy. At the endpoint, capsules were studied by fluorescence or electron microscopy. Mitotic activity was identified using Bromo-2-deoxyuridine labeling and detection techniques. When required, an intraocular lens was implanted when surgery was performed.
It was found that human lens cells from a wide age spectrum of donors proliferate and migrate on the lens capsule in the absence of added protein. The rate of growth was age-dependent, such that the posterior capsule was completely confluent after 8.0 +/- 0 days (n = 3) and 24.4 +/- 5.3 days (n = 3) for donor lenses aged < 40 years and > 60 years, respectively. The outgrowth of epithelial cells gave rise to capsular contraction, wrinkling, and increased light scatter. Growth on the anterior surface of the intraocular lens was less prolific than on the posterior capsule.
The protein-free model replicates many features of clinically-observed PCO. The resilient cell growth on the natural collagen capsule explains the high prevalence of PCO, especially in younger patients, and suggests that inflammation and external growth factors are not necessary for PCO. Furthermore, the protein-free capsular bag system can be used to explore fundamental questions concerning the autocrine control of lens epithelial cell survival and growth.
眼内液蛋白质含量相对较低，但在白内障囊外摘除术（ECCE）后，人晶状体囊袋内仍会发生细胞生长。这种顽强的生长在相当比例（30%）的患者中导致后囊膜混浊（PCO）。本研究比较了人晶状体细胞在补充血清和无蛋白培养基中的增殖能力。
对人类供体眼进行假白内障手术。将囊袋分离出来，平铺固定在培养皿上，分别置于单纯的伊格尔氏基本培养基（EMEM）或添加10%胎牛血清的EMEM中培养。通过相差显微镜进行观察。在实验终点，采用荧光显微镜或电子显微镜研究囊袋。使用溴脱氧尿苷标记和检测技术鉴定有丝分裂活性。手术时，根据需要植入人工晶状体（IOL）。
研究发现，来自不同年龄范围供体的人晶状体细胞在未添加蛋白质的情况下，能在晶状体囊膜上增殖和迁移。生长速度与年龄有关，年龄小于40岁和大于60岁的供体晶状体，后囊膜分别在8.0±0天（n = 3）和24.4±5.3天（n = 3）完全融合。上皮细胞的生长导致囊膜收缩、起皱和光散射增加。人工晶状体前表面的生长不如后囊膜旺盛。
无蛋白模型重现了临床上观察到的PCO的许多特征。天然胶原囊膜上顽强的细胞生长解释了PCO的高发生率，尤其是在年轻患者中，并表明炎症和外部生长因子对于PCO并非必需。此外，无蛋白囊袋系统可用于探讨有关晶状体上皮细胞存活和生长的自分泌控制的基本问题。
