Annulus Fibrosus Injury Induces Acute Neuroinflammation and Chronic Glial Response in Dorsal Root Ganglion and Spinal Cord—An In Vivo Rat Discogenic Pain Model

This study investigates how damage to the annulus fibrosus (AF), a part of the spinal disc, leads to inflammation in the spinal cord and dorsal root ganglion (DRG), contributing to discogenic pain. The research uses a rat model where AF injury causes inflammation and changes in the DRG and spinal cord over time, mimicking the progression from acute to chronic pain. The findings suggest that treatments for discogenic pain should target both the spinal and nervous systems, focusing on managing acute inflammation early and addressing chronic inflammation and nerve sensitization later.

• 1
  AF injury induces acute inflammation in the spine, DRG, and spinal cord, followed by chronic glial responses in the DRG and spinal cord.
• 2
  Macrophage activity (CD68) increases in the spine after AF injury, peaking at 3 days and remaining elevated in the anterior AF for up to 8 weeks.
• 3
  AF injury leads to a sustained increase in satellite glial cell activation (GFAP) in the DRG and persistent spinal cord sensitization, as indicated by elevated substance P (SubP).