In vitro model of neurotrauma using the chick embryo to test regenerative bioimplantation

Effective repair of spinal cord injury sites remains a major clinical challenge. One promising strategy is the implantation of multifunctional bioscaffolds to enhance nerve fiber growth, guide regener­ating tissue, and modulate scarring/inflammation processes. Given their multifunctional nature, such implants require testing in models which replicate the complex neuropathological responses of spinal injury sites. This is often achieved using live, adult animal models of spinal injury. However, these have substantial drawbacks for developmental testing, including the requirement for large numbers of animals, costly infrastructure, high levels of expertise, and complex ethical processes. As an alternative, we show that organotypic spinal cord slices can be derived from the E14 chick embryo and cultured with high viability for at least 24 days, with major neural cell types detected. A transecting injury could be reproducibly introduced into the slices and characteristic neuro­pathological responses similar to those in adult spinal cord injury observed at the lesion margin. This included aligned astrocyte morphologies and upregulation of glial fibrillary acidic protein in astrocytes, microglial infiltration into the injury cavity, and limited nerve fiber outgrowth. Bioimplan­tation of a clinical grade scaffold biomaterial was able to modulate these responses, disrupting the astrocyte barrier, enhancing nerve fiber growth, and supporting immune cell invasion. Chick embryos are inexpensive and simple, requiring facile methods to generate the neurotrauma model. Our data show the chick embryo spinal cord slice system could be a replacement spinal injury model for laboratories developing new tissue engineering solutions.