One of the most challenging applications for tissue regeneration is spinal cord damage. There is nocure for this, partly because cavities and scar tissue formed after injury present formidable barriersthat must be crossed by axons to restore function. Natural silks are considered increasingly formedical applications because they are biocompatible, biodegradable and in selected cases promotetissue growth. Filaments from wild Antheraea pernyi silkworms can support axon regeneration inperipheral nerve injury. Here we presented evidence that degummed A. pernyi filaments (DAPF)support excellent outgrowth of CNS neurons in vitro by cell attachment to high density of arginineglycine-aspartic acid tripeptide present in DAPF. Importantly, DAPF showed stiffness propertiesthat are well suited to spinal cord repair by supporting cell growth mechano-biology. Furthermore,we demonstrated that DAPF induced no activation of microglia, the CNS resident immune cells,either in vitro when exposed to DAPF or in vivo when DAPF were implanted in the cord. In vitroDAPF degraded gradually with a corresponding decrease in tensile properties. We conclude that A.pernyi silk meets the major biochemical and biomaterial criteria for spinal repair, and may havepotential as a key component in combinatorial strategies for spinal repair.
Bibliographical noteThis work was supported by the Institute of Medical Sciences of the University of Aberdeen, Scottish Rugby Union and RS McDonald Charitable Trust. We are grateful to Mr Nicholas Hawkins from Oxford University and Ms Annette Raffan from the University of Aberdeen for assistance with tensile testing. We thank Ms Michelle Gniβ for her help with the microglial response experiments. We also thank Mr Gianluca Limodio for assisting with the MATLAB script for automation of tensile testing’s data analysis.
- biomaterials - cells