Survival and regeneration of adult human and other mammalian photoreceptors in culture

Abstract

Purpose: Fully mature neurons of central nervous system origin generally are considered unable to survive for extended periods of time in simple culture conditions. The authors report that adult and aged human, porcine, and rodent retinal neurons, including rod and cone photoreceptors, constitute an exception to this idea.

Methods: Cells were dissociated from human postmortem retinas, adult mammalian retinas, and selected brain regions and were seeded into tissue culture plates and left to develop as monolayer cultures for up to 2 months. A battery of antibody markers was used to identify the nature and morphology of the cells in vitro.

Results: Photoreceptor cell survival of rods and cones was observed routinely when the delay between the time of death until culture preparation was 50 hours or less, compatible with current eye bank practice. Two-week-old cultures were formed of rod photoreceptors, representing approximately 50% of neuronal cell types; cone photoreceptors, representing 5% to 30% of neuronal cell types; other retinal neurons (especially amacrine cells approximately 20%); and retinal glial cells, present in variable numbers. Glial cells were essential for long-term photoreceptor survival and neurite outgrowth. Adult mammalian brain neurons isolated under the same conditions did not survive.

Conclusions: Fully adult human and other mammalian retinal neurons, including photoreceptors, exhibit remarkable plasticity in vitro, and such monolayer models may have applications in physiological, pharmacologic, and toxicologic studies of human and other mammalian retina.