Development of a chemically extracted acellular muscle scaffold seeded with amniotic epithelial cells to promote spinal cord repair.

Bridging strategies are essential for spinal cord repair in order to provide a physical substrate allowing axons to grow across the site of spinal cord lesions. In this study, we have evaluated the therapeutic effects of adding amniotic epithelial cells to a unidirectionally oriented acellular muscle scaffold and have compared this with the effect of a scaffold alone. Chemically extracted acellular muscles, with or without amniotic epithelial cells, were implanted into the lateral hemisected adult rat thoracic spinal cord. Control rats were similarly injured. After 4 weeks, the acellular muscle scaffolds were found to be well integrated with the host tissue. The chemically extracted acellular muscle scaffold seeded with amniotic epithelial cells promoted axonal growth in a distinctly organized and linear fashion, induced sprouting of calcitonin gene-related peptide positive axons, and was not associated with an astrocyte response. Compared with acellular muscle scaffolds alone, the addition of amniotic epithelial cells further promoted the remyelination of nerve fibers, sprouting of 5-hydroxytryptamine nerve fibers, relays of cortical motor-evoked potential and cortical somatosensory-evoked potential, and functional recovery. All these data together suggest that co-implantation of chemically extracted acellular muscle with amniotic epithelial cells may constitute a valuable approach to study and/or develop therapies for spinal cord injury.