MSCs reduce neuronal cell death in glutamate-treated cortical neurons

Multiple sclerosis (MS) is a chronic immuno-mediated inflammatory and demyelinating disease characterised by the presence of both demyelinating lesions and axonal degeneration, which lead to the reduction of nerve conduction velocity and the development of concomitant neurological deficits. Recently, Mesenchymal Stem Cells (MSCs) have been proposed in in vivo studies as promising therapeutic treatment for MS mainly for their capacity to modulate the immune response, moreover, during our previous experiments we found that rat undifferentiated MSC promote Dorsal Root Ganglia neurons survival and maturation. The aim of this study is to verify the potential protective effect of MSCs on an in vitro model of MS represented by rat primary cultures of cortical neurons. Since glutamate excitotoxicity is an important mechanism in neurodegenerative diseases, and it induces neuronal alterations similar to those observed in advanced MS, cortical neurons cultures were treated with different concentrations of glutamate (25, 50, 100, 200 and 500 µM) for 24 hours. After the treatment cortical neurons show a suffering appearance, with damaged axons and cellular degeneration. Neuronal viability, assessed by DAPI staining and by count of viable cells, was glutamate dose-dependent. In order to evaluate the possible positive effect of MSCs on neuronal survival, both direct and indirect co-cultures of MSCs and cortical neurons were set up, and the survival after glutamate treatment analyzed. Cortical neurons treated with glutamate were still suffering after the direct co-cultures with MSCs, while in indirect co-cultures with MSCs neurons were alive, without important signs of axonal degeneration. These preliminary findings suggest that MSCs are able to reduce the cellular death induced by glutamate exposure in cortical neurons and encouraged the further study and characterization of their positive effect