Multichannel silk protein/laminin grafts for spinal cord injury repair

The physical, chemical, and bioactive cues provided by biomaterials are critical for spinal cord regeneration following injury. In this study, we investigated the bioactivity of a silk-based scaffold for nerve tissue remodeling that featured morphological guidance in the form of ridges as well as bioactive molecules. Multichannel/laminin (LN) silk scaffolds stimulated growth, development, and the extension of primary hippocampal neurons after 7 days of culture in vitro. And then, the multichannel/LN silk scaffolds were implanted into 2-mm-long hemisection defects in Sprague-Dawley rat spinal cords for 70 days to evaluate their bioactivities of spinal cord remolding. Our results demonstrated that animal behavior was significantly improved in the multichannel/LN group, as evaluated by Basso-Beattie-Bresnahan score, whereas the implantation of multichannels and random pores groups resulted in recurring limps. Moreover, histology and immunohistochemical staining revealed an increase in blood vessels and expression of growth associated protein-43 and neurofilament-200 as well as reduced expression of glial fibrillary acidic protein in the multichannel/LN group, which contributed to the rebuilding of spinal cord defects. Thus, multichannel/LN silk scaffolds mediated cell migration, stimulated blood capillary formation, and promoted axonal extension, suggesting the utility of these scaffolds for spinal cord reconstruction.