Jornal de Citologia e Histologia

The Role of the Basal Lamina in Nerve Regeneration

Abstract

García-Medrano B, Pérez CS, Sanz PB, García MG, Martín-Ferrero M and Rodríguez MJG

Introduction: In the context of axon regeneration, certain molecules containing the basal lamina, particularly fibronectin, laminin and heparin sulfate promote axonal elongation in vitro and in vivo. This structure could lead the axons to distal stump in nerve defect repair. Material and Methods: In twenty male Wistar rats, a critical defect of 15 mm was created in the sciatic nerve, which was bridged by an acellular muscle graft, which were obtained from the gluteus medius muscle of two donor rats, and chemically treated to cellular extraction by protocol consisted of 7 h in distilled water changed three times every 2-3 h, one night in Triton detergent, and 24 h in deoxycholate. After 90 days, the explanted pieces of sciatic nerve with grafts were carved and cut into seven pieces equally in all animals; pieces were processed in resin (toluidine blue staining) and also for paraffin embedding: hematoxylin-eosin and Masson trichrome. Results: Microscopically, proximal ends appeared as a normal nerve, with proper, regular and orderly fascicular distribution, perfectly defined by its three wraps, with little connective tissue. At the graft, regenerated axons used the muscle as a bridge, with many small nerve fascicles separated by host tissue and plenty of blood vessels. Axons followed their basal lamina, defining small fascicles with large vessels and abundant connective tissue. At the distal end, there was no a clear division in fascicles in some animals. There was little connective tissue between the fibers and the epineurium was quite developed. Conclusions: The selected biological method for chemical treatment of skeletal muscle achieves acellular grafts. We successfully could repair a critical lesion of the sciatic nerve in rats using this acellular muscle graft. Acellular muscle that we employed as a graft provides a bridge tool for the advancement of the regenerating axons, perhaps due to the structural proximity of laminin to nerve sheaths.