Addition of insulin-like growth factors (IGF-1) for the regeneration of critical defects in peripheral nerve injuries. Biological findings

Abstract

The purpose is analyze the biological and cellular regeneration of non-repairable lesions of peripheral nerve by muscle graft enhanced with growth factors. Methods: Controlled clinical experimental trial, level I evidence. Critical peripheral nerve injuries repair through acellular muscle graft alone versus its enrichment with IGF-1 (10 mg/ml mecasermin). Clinical and functional control for 3 months. Animals were sacrificed at 90-100 days, obtaining samples for macro and microscopy with blue toluidine staining, hematoxylin-eosin and Masson trichrome. Results: Regenerating axons can pass through a defect length of 15 mm with the addition of an acellular skeletal muscle graft and repopulate the distal nerve. Basal lamina tubes, acting as matrices for the axonal growth, appears that sensory recovery exceeds the rate of motor nerve fibers growth. Finding a number of regenerating axons greater than healthy sciatic, ensures the functional connection of distal axons to their target innervation. In contrast, grafts myelinated fibers are smaller than those of healthy sciatic nerve. Discussion: Acellular muscle fibers basal lamina define tubes that could support axonal regeneration, acting as matrices for the growth of axons, when grafted into a nerve defect. Stereologic studies biological sections to quantify the increase in the total number of axons, the density thereof and the thickness of the myelin from microscopic examination of histological slices of animals treated with the growth factor IGF-1.