Experimental Studies Of Preparing Nerve Growth Factor Microspheres And Improvement On Peripheral Nerve Defect

Objective: Prolonged delivery of neurotrophic proteins to the target tissue is valuable in the treatment of various disorders of the nervous system. In this study, we tested whether sustained release of nerve growth factor (NGF) within nerve guide conduits (NGCs), a device used to repair injured nerves, would augment peripheral nerve regeneration. NGF-containing polymeric microspheres fabricated from a biodegradable PLGA were loaded into PLA conduits to provide prolonged, site-specific delivery of NGF. Methods: The conduits were used to bridge a 10 mm gap in a rat sciatic nerve model. Three months after implantation, electromyogram examination and morphological analysis revealed higher values of fiber diameter, fiber amount and thickness of medullary sheath at the distal end of regenerated nerve cables collected from NGF microsphere-loaded PLA conduits, compared to those from control conduits loaded with either saline alone, or NGF protein without microencapsulation. Result: Beneficial effects on nerve conduction speed , fiber diameter, fiber amount and thickness of medullary sheath were also observed in the permeable PLA NGCs. Conclusion: These results confirmed a longterm promoting effect of exogenous NGF on morphological regeneration of peripheral nerves. The tissue-engineering approach reported in this study incorporated with a microsphere protein release system into NGCs holds potential for improved functional recovery in patients whose injured nerves can be reconstructed by entubulation.