Herpes Zoster

Abstract

Previously, we showed that CD137 ligand (CD137L; AKA 4-1BBL) contributes to the development of behavioral hypersensitivity and functional recovery in mice following peripheral nerve injury-induced neuropathic pain. Mice that lack CD137L showed reduced sensory sensitivity and faster functional recovery. Here, we sought to further investigate the potential involvement of lumbar spinal cord microglial responses in CD137L-mediated behavioral changes following sciatic nerve crush. Lumbar spinal cord microglia were isolated from both wild type B6 and CD137L knockout (KO)_B6 mice via positive selection based on CD11b expression using magnetic beads at days 0 (naïve), 3, 7, 14, 28 and 56 following sciatic nerve crush or sham surgery. Following RNA extraction, qRT-PCR were performed to examine cytokine/chemokine expression in isolated microglia. Our preliminary results suggest that male mice had more measurable cytokine/chemokine responses than female mice. Despite that many cytokines are below the detection levels, we were able to observe increased expression of several chemokines, CCL2, CCL3, CCL4 and CCL5 in microglia from CD137L KO mice, which appeared to peak early following injury (Days 3–14) than that in microglia isolated from WT mice. Future study will determine the involvement of microglial chemokine responses in CD137L mediated sensory hypersensitivity and delayed functional recovery following peripheral nerve injury.