Macrophage Membrane-Coated MnO2 Nanoparticles Provide Neuroprotection by Reducing Oxidative Stress after Spinal Cord Injury.

Secondary injury following spinal cord injury (SCI) results in a large production of reactive oxygen species (ROS) (e.g., H₂O₂) in the spinal cord microenvironment, which then leads to an excessive burst of inflammation and ultimately neuronal death. In this study, we prepared manganese dioxide (MnO₂) nanoparticles coated by macrophage membranes, named M@MnO₂, to cope with early ROS bursts in the SCI microenvironment. The biosafety and targeting ability of the MnO₂ nanoparticles were improved through the macrophage membranes. Successful preparation of M@MnO₂ was verified by transmission electron microscopy, Western blot, and dynamic light scattering. Small animal imaging showed that M@MnO₂ accumulated in large quantities at the site of SCI. In the early stages of SCI, M@MnO₂ effectively reduced the ROS content, as well as the hypoxia-inducible factor 1α (HIF-1α) content, malondialdehyde content, and superoxide anion content caused by ROS, further leading to a decrease in some of the proteins associated with inflammation at the site of SCI (CD11b, CD86, COX2, IL-1β, and iNOS), ultimately achieving neuroprotection and recovery of motor function. [ABSTRACT FROM AUTHOR]