Porcine ex vivo retina model to study retinal neurodegenerative diseases: Potential role of mesenchymal stem cells

Abstract

Aims/Purpose: Retinal neurodegenerative diseases (RND) are associated with a progressive degeneration and death of retinal cells. Recently, mesenchymal stem cells (MSCs) showed a protective role against retinal cells degeneration and apoptosis. However, due to the complexity of such diseases, there is the need to develop in vitro or ex vivo models which allow the study of RND pathogenesis and better understand the regenerative role of MSCs. Therefore, the aim of our study was to use porcine retinas to establish a possible ex vivo model of spontaneous neuroretinal degeneration and employ this model to evaluate the efficacy of human amniotic fluid stem cells (hAFSCs) on retinal cells undergoing damage.Methods: To this end, neuroretinal explants were obtained from pig eyes and placed over the porous membrane of a transwell plate. To induce a time‐dependent spontaneous retinal degeneration, explants were cultured for 24, 48, 72, 96 h, 5 and 8 days. The damage grade was assessed with qRT‐PCR and immunohistochemistry analyses for GFAP and TUNEL‐assay. Then, the explants were co‐cultured with hAFSCs up to 8 days to evaluate their effect on retinal cells death via propidium iodide (PI) staining.Results: Results demonstrated that the cultivation of retinal explants up to 8 days induced an increase in the gene expression of inflammatory (NF‐kB and TNF‐alpha), pro‐apoptotic (p21 and p53) and oxidative stress markers (NRF2). We also observed an increased expression of GFAP and CD11b, suggesting an activation of the microglia and up‐regulation of Müller cells. In addition, the cultivation time induced an increase in the number of apoptotic cells (TUNEL). However, interestingly, the cells death decreased after co‐cultivation with hAFSCs (PI staining).Conclusions: In conclusion, our data demonstrate that the prolonged cultivation of porcine ex vivo retina can induce a time‐dependent spontaneous degeneration able to simulate a model of RND. Of note, the co‐culture preliminary data suggest a protective effects of hAFSCs on retinal cells death.