High porosity collagen tube: an innovative medical device for nerve regeneration

Bridging the gap after a nerve transection has always been a top challenge in the field of neuroscience. The peripheral nervous system can regenerate after injury but to fill a gap needs to find a proper guide directing the axonal elongation. Many techniques and devices have been studied in order to promote nerve regeneration but are still inade- quate. The aim of this work is validating an innovative high porosity collagen tube (medical devices, MD) and comparing the nerve outgrowth through this MD to the already avail- able in clinical practice NeuroGen IntegraÒ collagen and the silicone tubes, as a standard control, in an animal model of traumatic injury. The conduits were implanted in a 10 mm- gap in rat sciatic nerve and retrieved at different time points for morphological and ultrastructural analysis. Nerve conduc- tion studies were also evaluated. Nerve outgrowth through the NeuroGen IntegraÒ devices appeared to be similar to the one in the silicone tubes, being characterized by mini- fascicles containing less small axons with thin myelin and without a well-organized blood vessels distribution in the en- doneurium. In contrast, our MD showed, in the regenerated mid-graft, a normal size and number of nerve fibers with a normal myelination (G-ratio), already evident at 60 days postoperatively. Moreover, perineurium and blood vessels appeared absolutely normal with tight junction by EM. At 90 days postoperatively a nerve action potential was recordable distally, at the paw, in the sciatic nerves of the rats implanted with our MD or with the NeuroGen ones whereas was absent in the silicon group. Overall the neurophysiologi- cal and neuropathological data demonstrate the terrific qual- ity of nerve regeneration using our MD. These results make us confident in proposing our MD in the clinical practice to treat injury of the PNS.