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Abstract #5952 Published in IGR 2-2
mRNA in situ hybridization of TIGR/MYOC in human trabecular meshwork
Wang X; Johnson DHInvestigative Ophthalmology and Visual Science 2000; 41: 1724-1729
PURPOSE: To determine the distribution of mRNA expression of the trabecular meshwork-induced glucocorticoid response protein/myocilin (TIGR/MYOC) in human trabecular meshwork. METHODS: In situ hybridization using a 1.25-kb probe obtained from reverse transcription-polymerase chain reaction of TIGR/MYOC cDNA was performed to determine the location of cell labelling within the different regions of the meshwork. The effect of dexamethasone on the pattern of labelling was studied in organ cultured meshwork. Trabecular meshwork from three sources was studied: enucleated eyes obtained at autopsy, trabeculectomy specimens obtained during filtration surgery, and meshworks from anterior segments in perfusion organ culture. Hybridization was performed on frozen sections, paraffin sections, and sections from JB-4 plastic-embedded tissue. RESULTS: Labelling for TIGR/MYOC mRNA was present in most trabecular cells of the uveal, corneoscleral, and juxtacanalicular regions but only variably present in the endothelial cells of Schlemm's canal. A similar pattern was found in the trabeculectomy specimens from eyes with primary open-angle or pseudoexfoliative glaucoma. Dexamethasone treatment increased the labelling intensity and number of labeled cells in meshwork, and also the number of labelled endothelial cells of Schlemm's canal. Fresh tissue processed within 12 hours postmortem gave more consistent labelling than older tissue, although some label was found up to 48 hours postmortem. Labelling was found in tissue from all three sources, and with all three embedding techniques; JB-4 sections provided the best morphological resolution. CONCLUSIONS: In situ hybridization reveals that mRNA expression for TIGR/MYOC is present in most cells in all regions of the meshwork but only variably present in the endothelial cells of Schlemm's canal. Dexamethasone treatment increased the number and intensity of labelled cells, and also increased the number of labelled cells in the endothelial lining of Schlemm's canal.
Dr. X. Wang, Department of Ophthalmology, Mayo Clinic and Mayo Foundation, Rochester, MI 55905, USA
Classification:
1.2 Population genetics (Part of: 1 General aspects)
