Migration, Integration, Survival, and Differentiation of Stem Cell-Derived Neural Progenitors in the Retina in a Pharmacological Model of Retinal Degeneration

Purpose. The purpose of this work was to evaluate the retinal integration and differentiation of neurospheres formed by stem cells and mouse neural progenitor cells injected intravitreally in mice eyes with retinal injury. Methods. Eight male C57BL mice, 8 weeks old, were submitted to intraperitoneal injection of sodium iodate (2% NaIO3, 50？mg/kg). After 72 hours, 2？μL of solution with mNPC were injected intravitreally (100.000？cells/μL). After 7 days, their eyes were dissected and cryoprotected in 30% sucrose in PB for at least 24 hours at 4°C. The material was analyzed by immunohistochemistry and the following primary antibodies evaluation. Results. The results showed that the grafted cells integrated and survived in the adult mice within the sinner retinal tissue for at least 7 days. Immunohistochemical analysis revealed mature neuronal pattern in some regions. The mNPC population in the transplants was tightly surrounded by neuroretinal cells, suggesting their active role in neuron survival. Notably, the appearance of GFP-positive mNPC was not the result of fusion between donor cells and endogenous neuroretinal cells. Conclusions. Migration, survival, and differentiation of mNPCs were observed after 7 days following a single application with neurosphere method. The results may be clinically relevant for future stem cell therapy to restore retinal degeneration. 1. Introduction Retinal degenerative diseases remain an important cause of blindness in current years. In those conditions retinal cells suffer progressive damage, which cannot be avoided or replaced by modern therapeutic approaches [1]. Cell-based therapies including neural and stem cells represent an excellent perspective for therapy of retinal degenerations by replacing degenerating or lost photoreceptors [2]. The purpose of this study was to evaluate the potential for migration, incorporation, survival, and differentiation of neurospheres containing murine neural progenitor cells (mNPC) and stem cells in a pharmacological model of RPE-degeneration in the mice. 2. Materials and Methods The work was conducted after approval by the Ethics Committee of Universidade Federal de S？o Paulo (UNIFESP). For harvesting and culturing of progenitor cells, mouse neural progenitor cells (mNPC) were obtained from E14 (embryonic day 14) C57BL/6-GFP (green fluorescent protein) (Center for Development of Animal Models for Medicine and Biology (CEDEME), Sao Paulo, Brazil) mouse embryos. The male fetuses were placed in a Petri dish containing PBS/2% glucose, and the dissection is made under magnifying lens. The