Abstract
Bone cancer pain (BCP) is a debilitating condition driven by spinal neuroinflammation and glial activation. Esketamine (ESK), an NMDA receptor antagonist, exhibits analgesic effects beyond receptor blockade, but its mechanisms in BCP remain unclear. Here, a rat BCP model was established by intramedullary injection of Walker 256 cells, followed by intrathecal ESK administration (20, 40, 60 µg). Pain behavior was assessed using Von Frey, Hargreaves, CatWalk, and open field tests. While histology confirmed tumor-induced osteolysis, ESK did not prevent bone destruction. Instead, ESK significantly reduced mechanical and thermal hypersensitivity, improved gait and anxiety-like behaviors, and suppressed microglial and astrocytic activation in the spinal dorsal horn. This was accompanied by reduced pro-inflammatory cytokine levels and inhibition of MAPK pathway activation. Pharmacological blockade of glia (fluorocitrate, minocycline) or MAPK signaling (SB203580, SP600125) reproduced these effects, confirming the contribution of glia-MAPK interactions. These findings indicate that ESK alleviates BCP by suppressing glial-driven neuroinflammation and MAPK signaling, highlighting its potential as a multimodal analgesic.
Data availability
The datasets used and/or analysed during the current study available from the corresponding author on reasonable request.
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We thank Home for Researchers editorial team (www.home-for-researchers.com) for language editing service.
Funding
This work was supported by the Key Speciality of Anhui Province (2022-AH-105), Scientific research project of Anhui Provincial Health Commission (AHWJ2023A30069), Bengbu Science and Technology Bureau project (20220115), Natural Science Key Program of Bengbu Medical University (2023byzd113, 2024byzd475), Research Project on the Inheritance and Innovation of Traditional Chinese Medicine of Anhui Province (2024CCCX272), Research Project of Anhui Natural Science for Colleges and Universities (2024AH051215), National Science Foundation for Young Scientists of China (82171216, 81901124), the National Clinical Key Specialty Construction Project-Oncology department (2023-GJZK-001), the Clinical Key Specialty of Zhejiang Province Anesthesiology (2023ZJZK001), the Key Supported Discipline of Jiaxing Medical Science-Anesthesiology (2023-ZC-001), the Zhejiang Province Compact yet High-performing Clinical Innovation Team (CXTD202502014), and the Mindray Joint Fund of Zhejiang Provincial Natural Science Foundation of China under Grant No.LMRZ26H090001.
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LC and CX designed the study. DW, ZZ, YZ, YT, KB, BG, KZ, YC, and HR performed the experiments. CX and HN analyzed the data. LC and DW drafted and revised the manuscript. All authors reviewed and approved the final manuscript.
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Cheng, L., Wang, D., Zhang, Z. et al. Esketamine attenuates bone cancer pain by suppressing MAPK signaling and glial activation in the spinal dorsal horn of rats. Sci Rep (2026). https://doi.org/10.1038/s41598-026-38137-y
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DOI: https://doi.org/10.1038/s41598-026-38137-y