IMMUNOHISTOCHEMICAL STUDY OF HUMAN OPTIC-NERVE HEAD ASTROGLIA

Immunocytochemical localization of glial fibrillary acidic protein (GF AP) has been used to study the distribution of astrocytes and their mo rphology in sections of the optic nerve (ON) of human eye. Although al l ON regions presented GFAP immunoreactivity, immunostained tissue was most common in the posterior prelaminar region (PR) and least common in the laminar region (LR). Two shapes of astrocytes were distinguishe d: thick and thin bodied astrocytes. Astrocytes with thick cell bodies are located in the superficial nerve fiber layer (SNFL), PR, LR and r etrolaminar region (RR). Astrocytes with thin cell bodies were found i n the SNFL and anterior PR. Sometimes thin bodied astrocytes presented another shape with a long process running parallel to the axons and t hese were found in the PR and LR. In the SNFL the thin bodied astrocyt es accompany the axons and contact the capillaries derived from the ce ntral retinal artery, In the anterior PR the thin bodied astrocytes wi th a stellate shape lie over the vessels forming a sieve through which the axons pass. In the posterior PR, the thick bodied astrocytes form glial tubes that direct axons towards the LR. These astrocytes form a layer in the LR that lines the pores of the lamina cribrosa and separ ates the connective septa from the axon bundles in the RR. The limitin g glial membranes separate the ON tissues from the adjacent tissues an d from the course of the central retinal artery and are composed of ma ny thick bodied astrocytes. Copyright (C) 1996 Elsevier Science Ltd.