Tissue Engineered Nerve Conduits: The Use of Biodegradable Poly-DL-lactic-co-glycolic Acid (PLGA) Scaffolds in Peripheral Nerve Regeneration
Introducion. Tissue engineering holds great promise for nerve replacement and restoration. The present study evaluated the efficacy of utilizing poly-DL-lactic-co-glycolic acid (PLGA) formed tubes through an extrusion process for peripheral nerve regeneration.
Material and Methods. Conduits were manufactured by dissolving 75:25 PLGA in methylene chloride, and salt crystals (150 and 300 µm) were added to the polymer solution. The formed suspension was allowed to evaporate, and the resulting PLGA/salt composite disks were cut, placed into a piston extrusion tool, and heated to 250 °C. After heating, the PLGA/salt composite was extruded to form a tube with an inner diameter of 1.6 mm and an outer diameter of 3.2 mm. Twenty Sprague Dawley (250 g) rats were anesthetized and had the 12-mm PLGA conduits interposed into the right sciatic nerve using 10-0 nylon sutures under microsurgical technique. Functional evaluation was performed monthly by walking track analysis. At 16 and 12 weeks, electrical conduction was performed and sections of the proximal, grafted, and distal nerve were harvested for histomorphometric analysis.
Results. All conduits remained flexible, allowing mobility of the rat extremity without breakage. No severe inflammatory reaction could be identified, and no neuromas were apparent clinically. Evaluation of the Sciatic Functional Index demonstrated improved functional recovery, noting muscle reinnervation; however, no electrical conduction could be elicited. Histomorphology demonstrated axonal migration and nerve tissue advancement through the entire conduit and into the distal nerve stump at 12 weeks. The number of axons/mm2 and nerve fiber density in the distal nerve was 5793 and 0.2231, respectively.
Conclusion. Each year, the prolonged recovery from traditionally treated nerve injuries results in millions of dollars in lost revenue and increased compensation benefits. The proposed methodology for peripheral nerve restoration described herein has the potential to lead to more cost-effective and less morbid strategies for nerve replacement.
KeywordsNerve Growth Factor Sciatic Nerve Schwann Cell Nerve Regeneration Nerve Graft
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