GLIAL CELL RESPONSE AFTER CELLULAR THERAPY WITH HUMAN MESENCHYMAL STEM CELLS IN AN ACUTE GLAUCOMA MODEL

Glaucoma is the second leading cause of blindness in the world and is characterized by the gradual loss of vision. In this disease, the optic nerve is damaged, progressively causing degeneration of the retinal ganglion cells (RGC). To mimic the disease and test possible therapies, we used the optic nerve crush injury model. In this model, our group has already demonstrated that the intravitreal injection of mesenchymal stem cells (hMSC) is capable of inducing the survival of RGC, as well as promoting the regeneration of axons up to the encephalic targets. In the central nervous system (CNS) there are cells responsible for metabolic support and defense, such as astrocytes and microglia. After an injury in the CNS, those cells respond in different ways to the insult. Therefore, this work aims to evaluate the effects of hMSCs therapy on glial cells after nerve crush. To this end, astrocytic reactivity will be assessed in the retina in a short window of 3, 5 and 7 days post-injury by immunohistochemistry for GFAP, as well as for specific markers of astrocytic profiles A1 (neurotoxic) and A2 (neuroprotective), C3 and S100a10, respectively. qPCR analyzes will also be performed for astrocytic profile A1(C3, GBP2, H2-D1, and Serping1) and A2 (S100A10, pentraxin-3, S1Pr3, and Tweak). Microglia response will be evaluated by immunohistochemistry against IBA-1 and CD68 antigens. Initially, using confocal microscopy, we quantified the area covered by GFAP in wholemount retinas of vehicle and hMSC treated rats. Seven days after the lesion and vehicle injection, there was a significant (p≤0.05) increase of 68% (1.68 ± 0.05; n=6) in the GFAP area in relation to naïve animals (1.00 ± 0.03; n=6). There was also a significant (p≤0.05) increase of 67% (1.67x ± 0.05; n=6) of GFAP area in retinas of hMSC. However, there was no significant (p=0.99) difference between vehicle and hMSC groups. Further investigations are necessary to understand whether and how the modulation of glial cells influences the positive results of neuroprotection and regeneration induced by cell therapy that we recently demonstrated.