ABSTRACT
PURPOSE: To identify a casual pathway between the alteration in visual experience, due to form deprivation and hyperopic defocus, and the increase in eye growth, we searched for candidate genes having regulatory effects on eye growth under myopic conditions. METHODS: The expression of the brain-derived neurotrophic factor, neurotrophin-3, sonic hedgehog, nerve growth factor, Six-3 and the Lh-2 group of genes in the transcriptional level after experimentally induced myopia (form-deprivation by goggles and by hyperopic defocus using negative spectacle lenses) were evaluated by semiquantitative reverse transcriptional polymerase chain reaction and Northern blot analysis. RESULTS: Results showed that only the sonic hedgehog gene was differentially expressed in the experimentally induced myopic retinal samples compared with controls. CONCLUSIONS: The sonic hedgehog gene may have regulatory functions in the signaling of the cascade of events that leads to axial elongation and vitreous enlargement of the eye under myopic conditions.
Subject(s)
Eye Proteins/genetics , Myopia/metabolism , Nerve Growth Factors/genetics , Proteins/genetics , Sensory Deprivation , Trans-Activators , Animals , Blotting, Northern , Brain-Derived Neurotrophic Factor/genetics , Chickens , DNA Primers/chemistry , Eye Proteins/biosynthesis , Gene Expression , Hedgehog Proteins , Homeodomain Proteins/biosynthesis , Homeodomain Proteins/genetics , Male , Myopia/etiology , Nerve Growth Factor/genetics , Nerve Growth Factors/biosynthesis , Nerve Tissue Proteins/biosynthesis , Nerve Tissue Proteins/genetics , Neurotrophin 3/genetics , Protein Biosynthesis , RNA, Messenger/biosynthesis , Reverse Transcriptase Polymerase Chain Reaction , Transcription Factors/biosynthesis , Transcription Factors/genetics , Homeobox Protein SIX3ABSTRACT
The purpose of this study was to evaluate changes in the expression of different genes in chick retinal tissues after induction of experimental myopia and to evaluate the roles of these genes in the regulation of postnatal eye growth and myopia. Form-deprivation using occlusive goggles and hyperopic defocus by negative spectacle lenses were used to induce myopia in hatched chicks. Expression levels of Sonic hedgehog, its receptor complex, and other retinal cell genes were evaluated by semi-quantitative reverse transcription-polymerase chain reaction. Levels of Sonic hedgehog protein were further evaluated by Western blot analysis. The induction of myopia caused significant increase in expression of Sonic hedgehog mRNA and protein and increased expression of blue and red opsin mRNA. In contrast, the expression of mRNA for Sonic hedgehog receptor complex (Patched-Smoothened), rhodopsin, vimentin, green opsin, violet opsin, and HPC-1 were unaffected by the induction of myopia. The increase in expression of Sonic hedgehog in chick retinas in experimentally-induced myopia suggests involvement in the retina control of postnatal eye growth. Furthermore, Sonic hedgehog may influence the expression of blue and red opsins under myopic conditions.
Subject(s)
Chickens/physiology , Myopia/genetics , Rod Opsins/genetics , Animals , Blotting, Western , Gene Expression , Male , Ocular Physiological Phenomena , RNA, Messenger/analysis , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
BACKGROUND: Fifty patients diagnosed with choroidal neovascularization in age-related macular degeneration were examined by indocyanine green videoangiography. Results were correlated with fundus photographs and fluorescein angiograms. Two patients were diagnosed with the macular variant of idiopathic polypoidal choroidal vasculopathy. CASES: Two middle-aged hypertensive women were diagnosed with macular idiopathic polypoidal choroidal vasculopathy. Throughout the follow-up period, both cases showed improved signs and symptoms without worsening of visual acuity, and despite the absence of definitive therapy. OBSERVATIONS: Indocyanine green videoangiography demonstrated the characteristic polypoidal lesions in idiopathic polypoidal choroidal vasculopathy better than fluorescein angiography, particularly when blood, exudates, or pigment epithelial detachments blocked visualization of the lesions. CONCLUSIONS: Incidence of idiopathic polypoidal choroidal vasculopathy may not be as low as reported, as its presentation mimics choroidal neovascularization in age-related macular degeneration. Differentiation can be made only through indocyanine green videoangiography. Conservative management may be beneficial, as visual prognosis is good.
Subject(s)
Choroid Diseases/diagnosis , Choroid/pathology , Coloring Agents , Fluorescein Angiography/methods , Indocyanine Green , Macula Lutea/pathology , Vascular Diseases/diagnosis , Video Recording , Diagnosis, Differential , Female , Fundus Oculi , Humans , Middle AgedABSTRACT
PURPOSE: To identify genes that are highly expressed in form-deprived retina-retinal pigment epithelium-choroid tissues. Neuroendocrine-specific proteins were found to be highly expressed. METHODS: mRNAs enriched in retina-retinal pigment epithelium-choroid tissues from 3-, 7-, and 14-day form-deprived chick eyes were isolated by differential display technique with cDNA library screening. Neuroendocrine-specific protein A and C were cloned in control and form-deprived eyes. mRNA and protein levels, with respective regional localizations, were examined by Northern blot, Western blot, and immunohistochemical analyses, respectively. RESULTS: The isolated clone included an insert with a sequence homologous to both chick neuroendocrine-specific proteins A and C. The increases in mRNA and protein levels were confirmed by Northern and Western blot analyses, respectively. Immunohistochemical localization of neuroendocrine-specific proteins A and C was detected in the layer of photoreceptor inner segments, presumably in the cone cells. Northern blot analysis using negative lenses showed that levels of neuroendocrine-specific protein A and C mRNAs were not altered using negative lenses. CONCLUSIONS: The expression of both neuroendocrine-specific proteins A and C mRNAs in cone photoreceptor cells was upregulated within 14 days of form deprivation, but not in response to negative spectacle lenses. These data suggest that the increase in induction of neuroendocrine-specific proteins is not a secondary consequence of ocular elongation or myopic refraction. Induction of neuroendocrine-specific proteins in form-deprived eyes may be causally related to the development of myopia or may be an unrelated effect of form deprivation.
Subject(s)
Eye/metabolism , Myopia/genetics , Nerve Tissue Proteins/genetics , RNA, Messenger/biosynthesis , Sensory Deprivation , Animals , Blotting, Northern , Blotting, Western , Chickens , Choroid/metabolism , Gene Expression , Immunoenzyme Techniques , Light , Male , Myopia/etiology , Myopia/metabolism , Myopia/pathology , Nerve Tissue Proteins/biosynthesis , Pigment Epithelium of Eye/metabolism , Retina/metabolismABSTRACT
Form-deprivation of chicks during early postnatal development results in ocular enlargement and great myopic refractive error (form-deprivation myopia). Previous studies have indicated that the retina, RPE and choroid play important roles in ocular enlargement in form-deprivation myopia. We aimed to isolate genes up-regulated in the retina-RPE-choroid of form-deprived chick eyes. A suppression subtractive hybridization method was used to compare mRNA expression in the retina-RPE-choroid of form-deprived and control eyes. One up-regulated cDNA was isolated and identified as part of chick delta1-crystallin cDNA. Northern blot and RT-PCR analyses demonstrated that delta1-crystallin mRNA was up-regulated in the retina-RPE at day 7 after form-deprivation treatment. Semi-quantitative RT-PCE analysis of the expression of several transcription factors indicated that Sox1 and Sox3 were upregulated in parallel with delta1-crystallin mRNA in form-deprived eyes. Northern blot analysis demonstrated that alphaA-, betaA3/A1-, betaB1-, and betaB2-crystallin mRNAs were also up-regulated in form-deprived eyes. Although the detailed mechanisms and functions of the crystallin family genes in the retina-RPE-choroid of form-deprived eyes remain unclear, results of our study suggests that form-deprivation affects the expression of these genes in chick eyes.
