Abstract
Purpose: :
Transplant of photoreceptor progenitors offer hope for treating retinal degeneration disease in mice, since these cells have taken the first steps toward becoming mature photoreceptors and can be integrated into diseased retinas. In this study, isolation and differentiation of human fetal photoreceptor progenitors were investigated.
Methods: :
Expression of rod opsin and transcription factor Nrl and CRX was assessed by immunocytochemistry (ICC) from frozen human fetal eyes ranging from fetal week 9 (Fwk 9) to Fwk 22. Mild separation techniques, including low dose of papin (1u/ml) and very gentle shaking, were adopted to get highly enriched photoreceptor progenitors from fetal retinas from Fwk 12 to Fwk 16. Cells were cultured in Neurobasal supplemented with EGF (40ng/ml) and bFGF (40ng/ml), retinoic acid was added to study photoreceptor progenitors differenriation. ICC labeling was performed for above-mentioned markers in cultured and differentiated cells.
Results: :
Nrl-positive cells appeared abundantly around Fwk 12, opsin-positive rods were detected clearly after Fwk 16. We can get more than 1 x 106 cells by mild isolation in one fetal eye. Purity of cultures was routinely more than 85% photoreceptor progenitors, with a Nrl-positive and opsin-negative expression. Retinoic acid stimulated these cells into opsin-positive ones.
Conclusions: :
High amount of photoreceptor progenitors are isolated from developing human fetal retina. These cells differentiate into mature photoreceptors in vitro. This study suggests that photoreceptor progenitors may reach the requirement of ideal seeds for clinical therapy of retinal degeneration.
Keywords: photoreceptors • immunohistochemistry • retinal culture