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@#Congenital cataract is one of the leading causes of childhood blindness and congenital membranous cataract is a rare and special type of congenital cataract. The lens fibre of congenital membranous cataract is degenerative and its cortex is absorbed gradually. Congenital membranous cataract also has another name, pseudoaphakia, due to the similar phenotype with posterior capsule opacification after cataract surgery, but without intraocular refractive power. There are few reports on congenital membranous cataract at home and abroad, and the research on the pathogenesis of congenital membranous cataract is even less. Clarifying the pathogenesis of congenital membranous cataract, especially the genetics, is very helpful for us to understand the pathogenesis of congenital cataract and the molecular mechanism of lens development.
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@#Regarded as a complex biological process, lens development involves a range of signal molecules and their crosstalk networks. Recently,the role of planar cell polarity(PCP)signaling pathway in lens development has attracted increasing attention. It has been reported that PCP is critical for lens morphology and transparency maintaining. The studies performed on PCP serve to provide guidelines on how to optimize the morphology of regenerated lens. This is thought as presenting an effective therapy for infant cataract from a clinical perspective. This article will give a comprehensive review of the role of PCP signaling pathways in the lens development.
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Epigenetics is the study of genomic structural modifications that affects gene expression without DNA sequence change.Epigenetic mechanisms for the regulation of gene expression include DNA methylation,histone modifications,and microRNAs.DNA methylation may contribute to silencing gene expression which is a major mechanism of epigenetic gene regulation.DNA methylation regulatory mechanisms in lens development and pathogenesis of cataract represent exciting areas of research that have opened new avenues for association with aging and environment.This review concludes current understanding of the major mechanisms and function of DNA methylation in lens development,pathogenesis of age-related cataract,secondary cataract and complicated cataract.By understanding the role of DNA methylation in the lens disease and development,it may help to develop a new therapeutic approach to clinical treatment of cataract.
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For the study the effects of X -ray irradiation on the development of lens and interactions between optic vesicle and lens, 200 rads X -ray irradiated to the preganat rats (Sprague -Dawley strain) on gestation day 9.5. The rats were sacrificed daily from the gestation day 10.5 to 17.5, and investigated the development of lens with light microscope. The results were as follows; 1. The survival rate of X -irradiated rat fetuses was decreased significantly compared with that of the control group. 2. The mean body weight of the X -irradiated rat fetuses was decreased significantly compared with that of the control group. 3. The congenital anomalies of the eye in the rat fetuses after X -irradiation were anophthalmia, congenital aphakia, lens aplasia, lens luxation, and coloboma of the retina. 4. The critical period of lens development of the Sprague -Dawley rats was considered from GD 9. 5 to GD 10.0. 5. In the X -irradiated rat fetuses on gestation day 9.5, optic vesicle did not developed, but lens developed independently , and moved deeply toward the forebrain vesicle. According to above results, it could be concluded that the development of lens from surface ectoderm might be independent from the inductive influence of optic vesicle, and the movement of lens toward the forebrain vesicle could be mediated by chemotactic factors secreted from the brain vesicle. Further studies are needed to reveal the mechanisms of lens development and interaction between lens and brain vesicle.