生長因子在雞之實驗性近視所扮演角色之研究(2/2)
Date Issued
2002
Date
2002
Author(s)
楊長豪
DOI
902314B002185
Abstract
The prevention and treatment of myopia are important issue of public health in many countries, especially in Taiwan where the prevalence rate of myopia is extremely high. The most important complication of extreme myopia is retinal degeneration affecting the posterior pole that is associated with elongation of ocular axial length. Unfortunately, the actual mechanism of the development of myopia is still unknown
Studies of the sclera of chicks with form-deprivation myopia showed an increase in thickness and in mitotic activity in the cartilaginous sciera, caused primarily by increased amount of DNA synthesis and production of extracellular matrix within the posterior segment of the ocular globe. All these findings question a previous ¡§passive scieral stretch¡¨ hypothesis and give support to the idea of ¡§active scleral tissue remodeling¡¨. Active remodeling of connective tissues is a complex process. Cellular growth factors and matrix metalloproteinases may contribute to the delicate balance between degradation and synthesis of various extracellular matrix components. Growth factors probably release from the retina-retinal pigment epithelium (RPE)-choroid complex and modulate the tissue remodeling of sciera. Growth factors known to modulate fibroblast proliferation and the composition of the extracellular matrix, such as bFGF, and TGF-p, are the promising candidates. Robrer and Stell suggested that bFGF acts as a stop signal and TGF-f3 acts as a go signal to modulate postnatal ocular growth in the chicken. However, experimental data from several studies are controversial. Rohrer and Stell reported that the intravitreal and subconjunctival injection of bFGF prevented excessive eye growth in chicken with form deprivation myopia. Seto et al. found that the bFGF content were significantly lower in the sciera in the posterior region of the myopic eyes than in the control eyes. The bFGF content were similar in the retina-RPE-choroid complex in myopic and control eyes. The TGF-13 content was significantly higher in myopic eyes in both the retina-RPE-choroid complex and the sciera. However, Honda et al. found that axial elongation in form-deprivation myopia was correlated with the reduction of TGF-j3 in the retina-RPE-choroid complex. In addition, the roles of other growth factors or cell growth modulating factors, such as IGF and vasoactive
intestinal peptide, have not been investigated. The role of these cellular growth factors in the pathogenesis of myopia needs further investigation.
In the second year of experiment, we investigated myopia from protein level. Protein from retina-RPE-choroid and sciera of myopic and control eyes was extracted and analyzed with two-dimensional gel electrophoresis. Two-dimensional gel electrophoresis will provide the highest resolution for protein analysis. More et al. used this method to find the proteome of the rhodopsin-bearing post-Golgi compartment of retinal photoreceptor cells. Nishizawa et al used this method to characterize bovine retina proteins. In our experiments the difference of protein expression between myopic and control eyes will be examined and the candidate proteins will be further analyzed with N-terminal sequence analysis and mass spectrometry. In this project, we used this powerful tool to study the pattern of protein expression in myopic eyes and to find the candidate genes responsible for the development of myopia. In addition, pharmacological agents, such as atropine, and pirenzepine haven been reported to modulate ocular growth in experimental myopia. We also examined the effect of these agents on the growth factors protein expression.
SDGs
Publisher
臺北市：國立臺灣大學醫學院眼科
Type
journal article
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