Sleep Deprivation Activates Spinal Microglia via MitoROS Mediated mtDNA-cGAS- STING Signaling to Promote Postoperative Hyperalgesia

Abstract Background Sleep deprivation (SD) is a major risk factor for the chronification of postoperative pain, yet the underlying mechanisms remain poorly understood. Emerging evidence indicates that mitochondrial dysfunction and innate immune signaling may contribute to central sensitization and persistent pain. Methods We used a mouse model combining 48-hour SD with plantar incision (SD + I) to investigate the mechanisms linking SD to postoperative hyperalgesia. Mechanical pain sensitivity was assessed behaviorally, while spinal microglial activation, proinflammatory cytokine expression (IL-1β, IL-6, TNF-α), and mitochondrial function including structure, membrane potential, ATP production, and mitochondrial reactive oxygen species (MitoROS) levels were evaluated. The involvement of the mtDNA-cGAS-STING pathway was assessed using pharmacological interventions with the mitochondria-targeted antioxidant Mito-Tempo and the STING inhibitor C-176. Results SD significantly prolonged postoperative mechanical hyperalgesia and enhanced spinal microglial activation, accompanied by elevated IL-1β, IL-6, and TNF-α expression. SD + I mice exhibited mitochondrial structural damage, decreased membrane potential and ATP production, and excessive MitoROS accumulation. This mitochondrial stress caused the release of mtDNA into the cytosol, thereby activating the cGAS-STING signaling pathway. Treatment with Mito-Tempo or C-176 effectively suppressed microglial activation, reduced neuroinflammatory cytokine production, and alleviated postoperative hyperalgesia. Conclusions Mitochondrial oxidative stress plays a crucial role in sleep deprivation-induced postoperative hyperalgesia, excessive activation of which promotes mtDNA-cGAS-STING-mediated spinal microglial activation and prolonged hyperalgesia. The reversal of neuroinflammation and pain hypersensitivity by Mito-Tempo or C-176 emphasizes the mechanistic and therapeutic relevance of this pathway for preventing sleep deprivation-related postoperative hyperalgesia.