Morphological changes in injured retinal pigment epithelium and photoreceptor cells after transplantation of stem cells into subretinal space

Introduction: Degenerative retinal diseases are main cause of irreversible blindness. Stem cells therapy is a promising way in these diseases. Therefore, mesenchymal stem cells because of its safety can produce degenerated cells and can play important role in treatment. The aim of this study was to examine morphological changes in injured retinal pigment epithelium (RPE) and photoreceptor cells after transplantation of stem cells into subretinal space. Materials and Methods: Retinal pigment epithelium injury induced with retro-orbital sinus injection of sodium iodate in pigmented rats and following histological verification, ready for transplantation. The generation of retinal pigment epithelium cells from bone marrow stromal stem cells were done in two steps. First, Bone marrow stromal stem cells isolated from rat femoral bone and after passage three differentiated into retinal pigment epithelium cells. Generated cells transplanted into sub retinal space of animal model and after 30 days the morphological analysis such as retinal pigment epithelium layer and cell count in outer nuclear layer of retina performed. Results: Differentiated cells expressed high yield (±93) of specific markers (RPE65, CRALBP) in immunocytochemistry. These cells transplanted into injured pigmented layer and after 30 days showed improvement in retinal pigment epithelium and outer nuclear cell layer. In other words, the cell count in these layer increased in comparing to control group. Conclusion: The generation of retinal pigment epithelium cells from bone marrow stromal stem cells which in term of expression of specific genes are similar to native RPE cells, as well as after transplantation into damaged tissue can show physiological activity are very useful in treatment of degenerative eye diseases.