Soluble factor effects on glial cell reactivity at the surface of gel-coated microwires.

A basal lamina gel preparation was incorporated into a modified neuroinflammation cell culture model to test the system as a characterization tool for surface-modified microwires. The extent of gliosis at the surface of gel-coated microwires was quantified in response to titrating the cell culture with a number of soluble factors reported to be involved in reactive gliosis. Positive control conditions (1% FBS, 10 ng/ml bFGF, Neural Basal medium with B27 supplement) induced a layer of GFAP-expressing astrocytes to accumulate on all gel-coated microwires. Serum, inflammatory cytokines IL-1alpha and IL-1beta and the neural progenitor cell (NPC) proliferating growth factors bFGF and PDGF all increased the number of reactive cells on the gel, in agreement with their reported roles in cell activation, migration and proliferation at the site of injury. Technically, this study shows that a fetal neuron-glia culture system is well suited for characterizing the impact of electrode coatings designed to mitigate implant-associated gliosis, and for screening the effect of multiple soluble factors that promote and/or inhibit implant-associated gliosis. Scientifically, this study points to essential roles of serum and inflammatory factors to induce NPC activation and migration to the site of injury, where growth factors like bFGF and PDGF induce proliferation of cells that will eventually form the glial scar.