Cerium Oxide Nanoparticles Alleviate Neuropathic Pain by Modulating Macrophage Polarization in a Rat SCI Model

Chronic neuropathic pain (NP) frequently occurs after spinal cord injury (SCI) but lacks effective therapeutic options in the clinic. Numerous evidence indicates the involvement of macrophages activation in the NP, and the modulation of macrophages is promising for NP treatment. Macrophages are the main immune cells and have a significant function in mediating neuroinflammation. They are highly plastic and can polarize into the classical phenotype (M1) and the alternative phenotype (M2). Cerium oxide nanoparticles (CONPs) are redox-active rare earth nanomaterials. It has shown many fascinating biological properties such as anti-inflammation, anti-oxidation, anti-tumor, as well as free radical scavenging, and attracts increased interest for therapeutic application.

• 1
  The synthesized CONPs were 6.8 ± 0.5 nm in size, presenting a cubic morphology.
• 2
  Intrathecal injection of CONPs could significantly increase the mechanical PWT and thermal PWL of SCI rats.
• 3
  Molecular experiments results showed the expression of M2 macrophage-related markers (CD206, Arg-1, IL-10) were significantly increased, while that of M1 macrophage-related markers (CD86, TNF-α, iNOS) were downregulated after CONPs treatment.