Localization of the stress proteins alpha B-crystallin and trabecular meshwork inducible glucocorticoid response protein in normal and glaucomatous trabecular meshwork.

PURPOSE To examine the differential staining of two potential stress-response markers, alpha B-crystallin and the trabecular meshwork inducible glucocorticoid response protein (TIGR), in meshwork from normal and glaucomatous human eyes. METHODS Trabecular meshwork from 35 eyes from 23 donors with either primary open-angle glaucoma, pseudoexfoliative glaucoma, or low-tension glaucoma, and from age-matched normal eyes, was examined. Sagittal and tangential frozen sections were stained with polyclonal antibodies to alpha B-crystallin or TIGR and then by a fluorescent secondary antibody. RESULTS In normal eyes, labeling for alpha B-crystallin occurred in the subendothelial region of Schlemm's canal and outer corneoscleral regions, whereas TIGR labeling was found in the inner uveal meshwork region and the anterior portion of the meshwork. In contrast, in many glaucomatous eyes, labeling for alpha B-crystallin and TIGR occurred in more regions of the meshwork and appeared more intense than in normal eyes, regardless of the type or clinical severity of glaucoma. CONCLUSIONS The differences in localization of alpha B-crystallin and TIGR may relate to functional specialization within meshwork tissues. The increase in the staining for these proteins in glaucomatous eyes could involve environmental and genetic factors in the disease processes.