Abstract
Purpose: :
To evaluate a three dimensional, in vitro, retinal co-culture model, consisting of photoreceptors and retinal pigment epithelium (RPE) within a polymer-based scaffold. We hypothesize that a hydrogel-based, three-dimensional co-culture model may allow photoreceptors and RPE to assume cellular architecture, which mimics their in vivo hierarchy.
Methods: :
Photoreceptor cells were isolated from retinas of Nrl-GFP mice at different postnatal time points. These primary photoreceptors were combined with poly(ethylene glycol) polymer and photoreceptor media and photopolymerized to form a solid gel. Laminin was also added to some gels, pre-polymerization, in order to examine the impact of this protein, known for its role in neural development. Cells were encapsulated at low and high densities, and the resulting gels were cultured in photoreceptor media for up to 10 days. Gels were evaluated using live/dead cell viability assays for different time points during the culture period. GFP expression was also examined in the encapsulated cultures.
Results: :
Gel constructs with a higher density of cells exhibited prolonged cell viability over the culture period compared to low-density constructs. No difference in cell viability was observed between constructs containing cells isolated at earlier postnatal days (P2, P4) compared to later stage isolations (P7, P8). A slight increase in cell viability and GFP expression was noted in gel constructs containing laminin versus those that did not.
Conclusions: :
The postnatal day on which the cells are isolated appears to have little to no effect on longevity of the encapsulated cells; nonetheless, inclusion of laminin in the polymer constructs may aid cell survival and health.
Keywords: photoreceptors • retinal pigment epithelium