Characterization of Primary Rat Astrocytes: a Step Towards Optic Nerve Head on a Chip

Abstract

The mechanism by which elevated intraocular pressure (IOP) increases risk of glaucoma remains unknown. A proposed pathway suggests astrocytes sense optic nerve head (ONH) deformation due to increased IOP, triggering their conversion to a reactive phenotype. When reactive, they can promote axonal damage in retinal ganglion cells (RGCs), causing progressive vision loss in glaucoma patients. Most research aimed at understanding astrocyte mechanobiology has been conducted in monolayer culture systems using DiTNC1 cells, a brain-derived line of cells, rather than primary ONH astrocytes. Such 2D cultures are problematic because they induce baseline activation, restricting our ability to understand true cellular response to stressors. Based on research using 3D culture systems that yielded preliminary results with DiTNC1 cells, we aim to develop a 3D culture system that can be used to elucidate astrocyte mechanotransduction pathways using primary ONH astrocytes and contribute to the development of accurate in vitro models of glaucoma. Characterization of isolated rat ONH astrocytes revealed positive staining for the astrocyte markers connexin-43, glial fibrillary acidic protein (GFAP), and vimentin. These astrocytes can be used to more accurately model and understand glaucomatous pathology using our 3D culture system. With the hope of ultimately developing an “optic nerve head on a chip,” our model system will expedite assessment of potential astrocyte-targeted therapeutics, facilitating the identification of alternative and/or complementary treatments to current IOP lowering strategies.