Evaluating neuronal and glial growth on electrospun polarized matrices: bridging the gap in percussive spinal cord injuries

Abstract

One of the many obstacles to spinal cord repair following trauma is the formation of a cyst that impedes axonal regeneration. Accordingly, we examined the potential use of electrospinning to engineer an implantable polarized matrix for axonal guidance. Polydioxanone, a resorbable material, was electrospun to fabricate matrices possessing either aligned or randomly oriented fibers. To assess the extent to which fiber alignment influences directional neuritic outgrowth, rat dorsal root ganglia (DRGs) were cultured on these matrices for 10 days. Using confocal microscopy, neurites displayed a directional growth that mimicked the fiber alignment of the underlying matrix. Because these matrices are generated from a material that degrades with time, we next determined whether a glial substrate might provide a more stable interface between the resorbable matrix and the outgrowing axons. Astrocytes seeded onto either aligned or random matrices displayed a directional growth pattern similar to that of the underlying matrix. Moreover, these glia-seeded matrices, once cocultured with DRGs, conferred the matrix alignment to and enhanced outgrowth exuberance of the extending neurites. These experiments demonstrate the potential for electrospinning to generate an aligned matrix that influences both the directionality and growth dynamics of DRG neurites.

Alignment of Astrocytes Increases Neuronal Growth in Three-Dimensional Collagen Gels and Is Maintained Following Plastic Compression to Form a Spinal Cord Repair Conduit

“…Since this work and other reports [13][14][15][16]28,37 demonstrate aligned astrocytes are conducive for enhanced and directed neuronal growth, we postulated that this could provide a novel basis for an implantable device to bridge spinal cord injuries. Previous studies have shown how cells in tethered aligned collagen gels can be delivered to peripheral nerve injury sites, 29 but the requirement for external tethering and overall fragility of such devices makes this unsuitable for clinical CNS repair.…”

The role of the surface on microglia function: implications for central nervous system tissue engineering

“…The number of studies investigating the influence of surface features on glial cells is increasing, yet focused on astrocytes, mainly due to astrocytes' key role in the formation of the glial scar in response to an injury to the CNS [12]. Astrocytes have been found to orientate their filamentous structure according to the features of the surface [13][14][15][16].…”

Novel Promises of Nanotechnology for Tissue Regeneration

“…The neurites grew in a radial manner on the aligned nanofibers. Those that grew in the direction of the fibers had a faster growth rate than the others indicating that the aligned nanofibrous scaffolds served in guiding neurite orientation and cell alignment (Chow et al, 2007).…”