Abstract
Abstract: :
Purpose: Retinal progenitor cells (RPCs) are self–renewing, multipotent cells that can be isolated from the developing neural retina, integrate with the host retina, and differentiate into cells of the retinal lineage. We examined whether biodegradable polymer substrates could be used to deliver RPCs to the subretinal space of mice. We evaluated the survival, migration and differentiation of RPCs delivered on polymer substrates, compared to delivery with single cell injections. Methods: Retinal progenitor cells (RPCs) harvested from the retina of postnatal day 1 EGFP (Enhanced Green Fluorescence Protein) mice (C57BL/6 background) were isolated and maintained in culture. The biodegradable PLGA polymer (50:50 glycolic acid: lactic acid; 40kDa) coated with laminin was cultured with RPCs. After culture, the polymers were cut into 0.3x0.5mm size with a tissue chopper. The cut polymers were transplanted into the subretinal space of C57BL/6 mice and rd mice. We evaluated graft survival in vivo via a fluorescent fundus camera 1w, 2w and 4w after grafting. Eyes were enucleated, fixed in 4% paraformaldehyde, and sectioned at 1w, 2w and 4w after operation, and the sections then stained for markers of mature retinal neurons and astrocytes. Results: We have demonstrated that it is possible to deliver a biodegradable polymer seeded with RPCs to the mouse subretinal space, and evaluate survival in vivo via GFP expression. After transplantation, most RPCs remained in the polymer, with few cells migrating into the host retina. Grafted RPCs expressed nestin, NF200, GFAP, recoverin and PKC. Conclusion: Our results have shown that biodegradable polymers are effectively able to deliver RPCs to the mouse subretinal space. We submit that the use of biodegradable polymer/ progenitor cell composite grafts offer the possibility of applying tissue engineering techniques to transplant studies in the CNS, and the retina is an ideal site to develop such techniques.
Keywords: regeneration • retina • transplantation