Cycloastragenol Alleviates Bone Cancer Pain by Targeting Sirt1 to Inhibit Neuronal Ferroptosis and Promote M2 Microglial Polarization in the Spinal Dorsal Horn of Rats

Bone cancer pain (BCP) is a chronic and debilitating condition often accompanied by neuroinflammation, microglial activation, and neuronal damage, which are difficult to manage with current therapies. Cycloastragenol (CAG), a bioactive compound from Astragalus membranaceus, exhibits anti-inflammatory and neuroprotective activities, yet its potential in BCP remains unclear. This study aimed to investigate the analgesic effects and underlying mechanisms of CAG in a rat model of BCP. In this study, we induced BCP in rats and administered CAG to evaluate its therapeutic effects. Behavioral testing, Western blotting, immunofluorescence, and molecular docking were employed to assess pain behaviors, inflammation, microglial polarization, and ferroptosis markers. CAG treatment significantly attenuated BCP-related pain and suppressed inflammation, promoting a shift from pro-inflammatory M1 to anti-inflammatory M2 microglial phenotypes, while inhibiting ferroptosis in spinal cord neurons through activation of the Sirt1-Nrf2 pathway. Sirt1 knockdown via siRNA abolished these beneficial effects, and cellular thermal shift assays confirmed a direct interaction between CAG and Sirt1. These findings demonstrate that CAG alleviates BCP by modulating microglial polarization and inhibiting neuronal ferroptosis via Sirt1 activation, suggesting its promise as a multi-targeted therapeutic strategy for BCP and other neuroinflammatory pain disorders.