ABSTRACT
The present study explored a new approach to the production of tubular conduits designed for peripheral nerve repair. Poly(L-lactic acid) (PLLA) and polycaprolactone (PCL) membranes were obtained after solvent evaporation and wrapped around a mandrel. The effectiveness of nerve regeneration was compared with that obtained with polyethylene and PCL extruded prostheses 30 and 60 days after surgery. The comparison between extruded and membrane-derived tubes clearly showed structural differences that were directly proportional to the hardness and transparency. An important factor to be considered is that the fiber count indicated that membrane-derived PCL tubes provided a significantly greater number of axons 30 days after repair. Sixty days after the procedure, the greatest regenerative performance was obtained with PCL, regardless of tube construction method. An intense imunolabeling of S100, type IV collagen, and laminin could be observed in the tissue obtained from membrane-derived PCL and PLLA groups, indicating that such constructs were able to positively stimulate Schwann cell responses. Overall, the results provided evidence that membrane-derived conduits are an alternative preparation method for tubular prostheses for peripheral nerve regeneration.
Subject(s)
Absorbable Implants , Nerve Regeneration , Peripheral Nerve Injuries , Peripheral Nerves/surgery , Tissue Scaffolds , Animals , Axons/physiology , Axons/ultrastructure , Basement Membrane/ultrastructure , Biocompatible Materials , Female , Immunohistochemistry , Lactic Acid , Materials Testing , Microscopy, Electron, Scanning , Peripheral Nerves/physiology , Peripheral Nerves/ultrastructure , Polyesters , Polymers , Rats , Rats, Sprague-Dawley , Schwann Cells/ultrastructure , Solvents , Time Factors , Tissue Engineering/methodsABSTRACT
The aim of this study was to investigate stability and tissue response to poly (L-lactic acid) (PLLA) membranes implanted in sub-dermal tissue of rats. Membranes with and without plasticizer (triethylcitrate) were compared. Membranes without plasticizer were denser and more compact than those with triethylcitrate. Fifteen days and 30 days after implantation, the membranes with tissue adhered were removed and processed for light microscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). By 15 days post-implantation, membranes lacking plasticizer showed invasion of the pores by connective tissue. Thirty days after implantation, the pores of membranes with plasticizer were invaded by blood vessels, and multi-nucleated giant cells surrounded by globular units of the membranes. Membrane debris was also detected in the cytoplasm of multi-nucleated giant cells. These data show that the addition of plasticizer to PLLA results in a more porous membrane, therefore enabling them more suitable in tissue repair (than membranes without plasticizer).
