Avaliação da migração e integração de células-tronco mesenquimais ao tecido retiniano lesado: estudo experimental em ratos Wistar

Abstract

PURPOSE: To evaluate the migration, retinal integration and differentiation of bone marrowmesenchymal stem cells (BM-MSCs) injected into the vitreous cavity of rat eyes with retinal injury. METHODS: Adult rat retinas were submitted to laser damage followed by transplantation of DAPI (4',6-diamidino-2-phenylindol) and Quantum Dot-labeled BM-MSCs grafts. Host retinas were evaluated at two, four and eight weeks after injury/transplantation to assess the migration, integration and differentiation of BM-MSCs in the laser-injured retina. RESULTS: The grafted cells survived in the retina for at least eight weeks and almost all BMMSCs migrated into the neural retina, mainly in the outer nuclear layer (ONL), inner nuclear layer (INL) and ganglion cell layer (GCL) whereas a subset of grafted cells were found in the subretinal space after the transplantation. Immunohistochemical analysis with several retinal specific markers revealed, at eight weeks, that the majority of the grafted cells expressed rhodopsin, a rod photoreceptor marker, followed by parvalbumin, a marker for bipolar and amacrine cells. A few subsets of cells were able to express the glial marker, GFAP. However, grafted cells failed to express pan-cytokeratin, a retinal pigment epithelium marker. There was DAPI diffusion for adjacent cells of the retina. CONCLUSION: There is BM-MSCs migration toward the lesion site following intravitreal injection of the cells. It is not possible to assure that there is differentiation and incorporation of the stem cells into the retina of rats after injury. DAPI diffusion to adjacent cells may be a bias.