Activation of satellite cells in the dorsal root ganglia in a disc-punctured rat model

The neural mechanisms underlying discogenic low back pain caused by disc degeneration remain unclear. Previous studies demonstrated that satellite cells (SC) play an important role in neuropathic pain. Twenty adult female Sprague-Dawley rats were used. The rats were divided into two groups: a nucleus pulposus (NP) group whose discs were punctured to expose the NP (n = 10) and a sham-operated group whose annulus fibrosus surface was scratched superficially (n = 10). In this study, we investigated the expression and cellular distribution of glial fibrillary acidic protein (GFAP, a marker of SC activation) in the dorsal root ganglia (DRG) innervating the intervertebral discs using a retrograde tracing method and immunohistochemistry in a disc-punctured rat model. In the sham-operated group, GFAP-immunoreactive (IR) SCs were not detected. In the NP group, GFAP-IR SC became evident, and 49 +/- A 13% of neurons innervating the punctured discs were surrounded by GFAP-positive SCs. Our results were the first to provide evidence for a potential role of SCs in the neural mechanisms of discogenic low back pain caused by disc degeneration.