Interleukin-3 Modulates Macrophage Phagocytic Activity and Promotes Spinal Cord Injury Repair

Following spinal cord injury (SCI), the body needs to clear away damaged cells and myelin debris. Macrophages, a type of immune cell, help with this process. This study investigates the role of interleukin-3 (IL-3) in this cleanup effort after SCI. The researchers found that IL-3, which is produced by astrocytes (a type of brain cell), helps macrophages clear away lipid-rich debris after SCI. Blocking IL-3 hindered this process, leading to more inflammation and worse outcomes. Giving IL-3 improved the cleanup, protected nerve cells, and helped with recovery. This study suggests that IL-3 could be a potential therapeutic target for enhancing neural repair and functional recovery after SCI. By modulating macrophage activity, IL-3 may help create a better environment for healing and regeneration after spinal cord injuries.

• 1
  IL-3 expression was significantly upregulated post-SCI, peaking at 14 days post-injury (dpi) and persisting until 28 dpi. Notably, IL-3 was primarily secreted by astrocytes surrounding the lesion epicenter.
• 2
  Neutralization of IL-3 led to increased lipid droplet accumulation, along with markedly widespread of macrophages and decreased neuronal survival, resulting in severe motor deficits compared to controls.
• 3
  In situ injection of IL-3 reduced lipid droplet accumulation in macrophages, preserved neurons, promoted axon regeneration, and ultimately contributed to the recovery of motor function after SCI.