Chitosan tube bridging autologous nerve segments for the repair of long-segmental sciatic nerve defects

摘要

BACKGROUND:Previous tissue-engineered nerve studies have focused on artificial nerve and nerve cell cultures.The effects of regeneration chambers with autologous nerve bridging for the repair of nerve defects remain unclear.OBJECTIVE:To explore the feasibility and advantages of chitosan tube bridging autologous nerve segments for repairing 12-mm sciatic nerve defects in rats.DESIGN,TIME AND SETTING:A randomized,controlled,animal study using nerve tissue engineering was performed at the Animal Laboratory and Laboratory of Histology and Embryology,Liaoning Medical University from June 2008 to March 2009.MATERIALS:Chitosan powder was purchased from Jinan Haidebei Marine Bioengineering,China.METHODS:A sciatic nerve segment of approximately 8 mm was excised from the posterior margin of the piriformis muscle of Sprague Dawley rats.The two nerve ends shrank to form a 12-mm defect,and the nerve defect was repaired using a chitosan tube bridging autologous nerve segment (bridge group),a chitosan tube-encapsulated autologous nerve segment (encapsulation group),and a chitosan tube alone (chitosan tube alone group),respectively.MAIN OUTCOME MEASURES:Histological and ultrastructural changes of the injured sciatic nerve;number of regenerated myelinated nerve fibers;nerve conduction velocity;leg muscle atrophy;and sciatic nerve functional index.RESULTS:At 4 months after implantation,the chitosan tube was absorbed.The tube was thin,but maintained the original shape,and vascular proliferation was observed around the tube.In the bridge group,regenerative myelinated nerve fibers were thick and orderly,with a thick myelin sheath and intact axonal structure.The number of myelinated nerve fibers and nerve conduction velocity were significantly greater compared with the other groups (P < 0.01).Moreover,nerve and muscle function was significantly improved following chitosan tube bridging autologous nerve segment treatment compared with the other groups (P < 0.05 or P < 0.01).CONCLUSION:Chitosan tube bridging autologous nerve segments exhibited better repair effects on nerve defects compared with chitosan tubeencapsulated autologous nerve segments and a chitosan tube alone.This method provided a simple and effective treatment for long-segmental nerve defects.