Immunostaining of heat shock proteins in the retina and optic nerve head of normal and glaucomatous eyes

Purpose: To examine immunostaining of 60-kd and 27-kd heat shock proteins ( HSP 60 and HSP 27), which are known to increase cell survival in response t o stress, in glaucomatous retina and optic nerve head. Methods: Six postmortem eyes from patients with primary open-angle glaucoma , 6 eyes from patients with normal-pressure glaucoma, and 6 eyes from age-m atched normal subjects were studied by immunohistochemistry. The sections o f the retina and optic nerve head were examined after immunostaining with a ntibodies to HSP 60 and HSP 27. Results: The intensity of the immunostaining and the number of labeled cell s for heat shock proteins (HSPs) were greater in retina sections from glauc omatous eyes than in sections from normal eyes from age-matched donors. Ret inal immunostaining of HSP 60 was prominent in the retinal ganglion cells a nd photoreceptors, whereas immunostaining of HSP 27 was prominent in the ne rve fiber layer and ganglion cells as well as in the retinal vessels. In ad dition, retinal immunostaining of these HSPs exhibited regional and cellula r differences. Optic nerve heads of glaucomatous eyes exhibited increased i mmunostaining of HSP 27, but not HSP 60, which was mostly associated with a stroglial cells in the lamina cribrosa. Conclusion: The increased immunostaining of HSP 60 and HSP 27 in the glauco matous eyes may reflect a role of these proteins as a cellular defense mech anism in response to stress or injury in glaucoma. Clinical Relevance: These findings suggest that immunoregulation is an impo rtant component of glaucomatous optic neuropathy.