Roller culture of free-floating retinal slices: a new system of organotypic cultures of adult rat retina.

No experimental system exists to date for the in vitro study of retinal ganglion cell populations in a three-dimensional organotypic tissue environment. Here, we describe such a novel method for roller cultivation of adult retinas. Retinas of adult (1-3 months old) rats were cut into rectangular slices of approximately 1 mm(2). Free-floating slices were cultured on a horizontal rotating roller drum (50-60 rpm) in a dry incubator at 36.5 degrees C. During the first days of cultivation, primary flat retinal slices changed their configuration and transformed into ball-shaped tissue spheres (retinal bodies). Histological and immunocytochemical studies showed that the outer wall of the retinal bodies was formed by cell and fibre layers typical of mature retina with photoreceptors located on the outside. Initially, retinal bodies contained an inner cavity which later was completely obliterated and filled with glial cells, sprouting nerve fibres, and vascular structures. This culture system was further developed into a robust model of glutamate-induced neurotoxicity. Using a novel culture method of adult rat retina, preservation of the three-dimensional organotypic retinal cytoarchitecture was achieved, including survival of neurons in the ganglion cell layer and sprouting of nerve fibres of the axotomized retinal ganglion cells. This novel culture model promises to facilitate studies of retinal physiology and pathology.