Immunohistochemical localization of MYOC/TIGR protein in the trabecular tissue of normal and glaucomatous eyes.
OBJECTIVE
To examine immunohistochemically the localization of myocilin/trabecular meshwork inducible glucocorticoid response (MYOC/TIGR) protein in the glaucomatous and normal trabecular meshworks.


METHODS
Trabecular tissues were used from one eye with late-onset goniodysgenetic glaucoma, three with primary open angle glaucoma (one of which had the MYOC/TIGR gene mutation), two with exfoliation glaucoma and one without glaucoma. For light microscopic immunohistochemistry, frozen sections were stained by the avidin-biotin complex method using anti-MYOC/TIGR polyclonal antibody. For electron microscopic immunohistochemistry, the pre-embedding method using the same antibody was performed. Double immunostaining using both anti-MYOC/TIGR and anti-type VI collagen antibodies was done by the immunofluorescence method.


RESULTS
With light microscopy, immunoreactivity was seen in the whole trabecular meshwork of each of the specimens. No notable differences were detected in staining among the types of glaucoma, or between the eyes with and those without the gene mutation. Under electron microscopy, immunoreaction products were observed not only in the cytoplasm of the trabecular cells but also in the extracellular matrix, where staining was associated with the long-spacing collagen, fine granular materials and possibly microfibrils. With double immunohistochemistry, MYOC/TIGR was colocalized with type VI collagen in the trabecular meshwork.


CONCLUSIONS
In glaucomatous and normal trabecular meshworks, the MYOC/TIGR protein is distributed in the extracellular matrix colocalizing with type VI collagen.
Tawara
A
A
Department of Ophthalmology, University of Occupational and Environmental Health, Kitakyushu, Japan. tawara-a@med.uoeh-u.ac.jp
Okada
Y
Y
Kubota
T
T
Suzuki
Y
Y
Taniguchi
F
F
Shirato
S
S
Nguyen
T D
TD
Ohnishi
Y
Y
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003094:Collagen / Q000378:metabolism; D003598:Cytoskeletal Proteins; D017889:Exfoliation Syndrome / Q000378:metabolism / Q000473:pathology; D005136:Eye Proteins / Q000378:metabolism*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D005902:Glaucoma, Open-Angle / Q000378:metabolism* / Q000473:pathology; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D016253:Microscopy, Immunoelectron; D008875:Middle Aged; D014129:Trabecular Meshwork / Q000378:metabolism* / Q000648:ultrastructure; D000099179:Myocilin
D003094:Collagen; D003598:Cytoskeletal Proteins; D005136:Eye Proteins; D006023:Glycoproteins; D000099179:Myocilin