INFLAMMATORY ACTIVATION OF THE SATELLITE GLIAL CELLS IN THE DORSAL ROOT GANGLIA OF RAT EXPERIMENTAL NEUROPATHIC PAIN MODELS
| Authors | |
|---|---|
| Year of publication | 2013 |
| MU Faculty or unit | |
| Citation | |
| Description | The satellite glial cells (SGC) envelope the primary sensory neurons of the dorsal root ganglia (DRG) and react intensely to various types of nerve injury that induce neuropathic pain. Unilateral chronic constriction injury (CCI, n=64) and spare nerve injury (SNI, n=32) of the rat sciatic nerve were used as experimental models of neuropathic pain (NPP). NPP induction was tested by withdrawal threshold of mechanoallodynia and thermal hyperalgesia. Expression of TNFa, IL-6, their receptors and signaling proteins (TNFR1, TNFR2, IL-6R, gp130, STAT3, SOCS3) and mRNAs were investigated bilaterally by immunohistochemistry and in situ hybridization in both lumbar (L4-5) and cervical (C7-8) DRG 1, 3, 7 and 14 days from surgical treatment. The SGC were identified by colocalization with GFAP or GS. Ipsilateral hind paws of all rats operated on CCI/SNI displayed mechanoallodynia and thermal hyperalgesia while contralateral hind paws and forepaws of both sides exhibited no significant hypersensitivity. Expression of cytokines, their receptors and signaling proteins demonstrated inflammatory activation of the neurons and their SGC not only in DRG associated but also non-associated with injured nerve. A distinct expression of cytokines and their receptors was predominantly identified in SGC surrounding large-sized DRG neurons. Moreover, inflammatory activation of SGC was also observed in DRG of sham-operated rats indicating other kinds of trigger mechanisms than after traumatic nerve injury. The results suggest that inflammatory activation of SGC contributes to ectopic activation of the DRG neurons associated with injured nerve, but in other DRG may stimulate conditioning of neurons to nerve injury. |
| Related projects: |