Abstract
Abstract: :
Purpose: To investigate the turnover of the inner limiting membrane (ILM) at different stages of embryonic and adult life. The ILM is the basement membrane of the retina and is located between the retina and vitreous body. Its protein constituents, such as lamin, collagen 4 and 18, nidogen, and perlecan are synthesized by the lens and ciliary body. Following secretion into the vitreous, ILM proteins bind to cell surface receptors that are clustered at the retinal neuroepithelial endfeet for ILM assembly. Thus, a requirement for ILM assembly and turnover is the presence of ILM constituents in the vitreous. Methods: We investigated the abundance of all currently known ILM proteins in the embryonic, posthatched, and adult chick vitreous body. Results: Our data showed that ILM proteins are abundant in the embryonic, but all but absent in the adult vitreous. The decline of ILM protein synthesis in the eye occurs within 10 days posthatching. A similar high embryonic and low adult expression was also true for vitreous body proteins such as collagen II, tenascin, collagen IX, and fibrillin. Conclusion: This study suggests that the ILM and the vitreous are synthesized and assembled during embryonic eye development and are maintained without major turnover throughout life. We hypothesize a similar embryonic assembly and life–long maintenance for the human ILM and vitreous body.
Keywords: retinal development • vitreous • retina