Halfter Willi, Winzen Uwe, Bishop Paul N, Eller Andrew
Department of Neurobiology, University of Pittsburgh, PA 15261, USA.
Invest Ophthalmol Vis Sci. 2006 Aug;47(8):3586-94. doi: 10.1167/iovs.05-1480.
Congenital high myopia is an early-onset enlargement of the eye globes that carries a high risk for retinal detachment. The genetic basis for congenital high myopia has frequently been connected to mutations in genes encoding extracellular matrix proteins of the vitreous body (VB) and the inner limiting membrane (ILM). Why defective or missing VB and ILM proteins lead to an increase in eye size is unknown. The present study introduces the chick embryo as a model to study the role of ILM and VB in regulating eye size.
The ILM and VB were disrupted by injecting collagenase into the eyes of E5 chick embryos. The digestion of VB and ILM proteins was monitored by Western blot and immunocytochemistry. Eye size was assessed up to 9 days after the enzyme injections.
Intraocular injection of collagenase led to the disruption of the ILM and the VB by digesting their collagen constituents. Once disrupted, the ILM and the collagen II fibrillar network failed to regenerate despite continued synthesis of VB and ILM proteins. ILM and VB disruption resulted in eye enlargement of 50% within 4 days. The increase in eye size was greatly reduced by reconstituting the ILM.
The present data show that the ILM and the VB play major roles in the early regulation of eye size. The authors speculate that the integrity of the vitreoretinal border is an important factor in preventing congenital high myopia.
先天性高度近视是眼球早期增大的疾病，伴有视网膜脱离的高风险。先天性高度近视的遗传基础常常与编码玻璃体（VB）和内界膜（ILM）细胞外基质蛋白的基因突变有关。为何VB和ILM蛋白的缺陷或缺失会导致眼球增大尚不清楚。本研究引入鸡胚作为模型，以研究ILM和VB在调节眼球大小中的作用。
通过向E5期鸡胚眼内注射胶原酶来破坏ILM和VB。通过蛋白质印迹法和免疫细胞化学法监测VB和ILM蛋白的消化情况。在酶注射后长达9天评估眼球大小。
眼内注射胶原酶通过消化其胶原成分导致ILM和VB破坏。一旦被破坏，尽管VB和ILM蛋白持续合成，ILM和胶原II纤维网络仍无法再生。ILM和VB破坏导致4天内眼球增大50%。通过重建ILM，眼球大小的增加显著减少。
目前的数据表明，ILM和VB在眼球大小的早期调节中起主要作用。作者推测玻璃体视网膜边界的完整性是预防先天性高度近视的重要因素。
