Study On Deferoxamine-loaded Conduits To Relieve Iron Overload And Promote Peripheral Nerve Regeneration

The altered microenvironment caused by peripheral nerve injury plays an important role in delayed nerve regeneration and impaired functional recovery.Wallerian degeneration leads to an imbalance in iron homeostasis after injury,which increases intracellular oxidation levels and leads to stress in mitochondria and endoplasmic reticulum(triggers of inflammatory microenvironment).Therefore,functional nerve conduits with iron chelation would be beneficial for re-establishing a local regenerative microenvironment.However,iron homeostasis-targeted treatments for peripheral nerve injury are limited.In view of this,we constructed a deferoxamine(DFO)-loaded P(MMD-co-LA)functional scaffold(PDPLA/DFO)by electrospinning to repair sciatic nerve injury.The research aims to explore the iron chelation effect of this scaffold during nerve repair and its regulatory mechanism on the regenerative microenvironment(including the regulation of mitochondrial and endoplasmic reticulum stress on the inflammatory microenvironment).In vitro,PDPLA/DFO electrospun membrane can alleviate iron overload-induced inactivation of glutathione peroxidase 4(GPX4)in Schwann cells,alleviate the stress state of endoplasmic reticulum and mitochondria,and reduce apoptosis.In vivo experiments,the PDPLA/DFO catheter relieved organelle stress by reducing iron overload,rebuilt the local anti-inflammatory microenvironment,and promoted nerve regeneration.The main research contents of this paper are as follows:(1)P(MMD-co-LA)powder was synthesized by ring-opening polymerization method,and the successful polymerization was proved by NMR spectroscopy;then it was mixed with DFO to prepare PDPLA/DFO electrospun membrane by electrospinning method,and the electrospun film was prepared by electrospinning method.In vitro drug release experiments,scanning electron microscopy(SEM)and mechanical properties tests proved that the PDPLA/DFO electrospun membrane had good drug release properties,fiber structure and mechanical strength;finally,the electrospun membrane was co-cultured with Schwann cells and treated with CCK.-8and live-dead staining experiments proved its good biocompatibility.(2)PDPLA/DFO electrospun membranes were co-cultured with Schwann cells under the iron overload model,and the activities of intracellular glutathione(GSH)and GPX4 were detected,and intracellular reactive oxygen species(ROS),mitochondrial membrane potential,Mitochondrial and endoplasmic reticulum stress-related proteins and levels of apoptosis;the results indicated that the electrospun membrane could alleviate the elevated levels of intracellular oxidation and apoptosis of endoplasmic reticulum and mitochondrial stress pathways.(3)The PDPLA/DFO conduit was used to repair the sciatic nerve defect in rats.Through the histological analysis of the distal nerve,the results proved that the conduit can balance iron homeostasis and reduce the endoplasmic reticulum and mitochondrial stress caused by iron overload,inducing an anti-inflammatory type The formation of a microenvironment,thereby promoting the repair of the sciatic nerve.