Evaluation of the proliferative capacity of canine retinal pigment epithelial cells harvested from different regions of the fundus.

摘要

Purpose : Regional susceptibility to disease of the foveomacular region is challenging to model in rodents due to the absence of a region of enhanced cone photoreceptor density in these species. The canine retina has a well-defined cone photoreceptor enriched region known as the area centralis. We tested the hypothesis that the canine central retinal pigment epithelium (RPE) is less capable of proliferation in response to stress in culture using an established tissue culture model. Methods : We harvested RPE cells from young adult healthy mixed-breed dogs (n = 6 eyes) following humane euthanasia. Cells were harvested and separate low-density cultures were made from the RPE of the area centralis, nasal visual streak, superior peripheral retina and inferior peripheral retina. As cultures approached confluency, cells were fixed and immunocytochemistry for RPE65 and the cell proliferation marker Ki67 was performed. We quantified the number of Ki67 positive nuclei compared with all nuclei (DAPI nuclear counterstain). A repeated measures ANOVA with Bonferroni post-test was used to compare values from the area centralis with other regions of the eye. Results : As expected, the RPE cells of the area centralis contained no observable melanosomes. Cells from all regions expressed RPE65, supporting an RPE cell-type. There was no significant difference in the density of the cells, at the time of initial culture (p = 0.27), or at the time of assay (p = 0.2). The area centralis region (6.1 ?± 5.3% SEM) contained a significantly smaller proportion of proliferating cells than the superior peripheral retina (38.5 ?± 9.1%, p 0.05). Conclusions : Mature retinal pigment epithelium cells of the canine area centralis region have reduced capacity to proliferate. Our results are consistent with the hypothesis that the retinal pigment epithelium of the cone-rich canine area centralis remains in a more quiescent state. Regional cultures of dog retinal pigment epithelium could be used to further study the underlying causes of regional susceptibility to foveomacular disease involving the RPE. This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.