Preparation of mNGF-conjugated iron oxide nanoparticles and repair of peripheral nerve injury in rats under applied external magnetic field

Abstract

Peripheral nerve injury is a common injury that can result in various dysfunctions, such as movement and sensory disorders or permanent disabilities. Although the application of microsurgical techniques has been able to achieve accurate anastomosis at the nerve stump, the effect of nerve repair is still unsatisfactory. In recent years, the focus of research has become how to effectively improve the regeneration microenvironment after nerve injury. At present, there are several methods for the administration of exogenous neurotrophic factors, including systemic medication, local stratified puncture administration, and local application of a micro-osmotic pump. However, due to the fact that the half-life of neurotrophic factors is only 2-5 min and that these are easily inactivated in vivo, the clinical use of exogenous nerve growth factors has been limited. In the present work, using poly (lactic acid glycolic acid) copolymer as a wrapping material, conjugated mouse nerve growth factor to MNPs to prepare the magnetic mouse nerve growth factor-poly(lactic acid glycolic acid) copolymer nanoparticles by the single emulsion solvent evaporation method and its physicochemical properties were characterized. Subsequently, the drug distribution in vivo was observed by comparing magnetic resonance imaging T2∗ intensity values under the guidance of an external magnetic field at different time periods. Then, macroscopic, functional, electrophysiological, and histological assessments of nerves were performed at eight weeks after surgery. The results showed that the use of magnetic targeting therapy can accurately guide the aggregation of drugs, which induces the promoting of functional recovery.