Cibotii Rhizoma extract protects rat dorsal root ganglion neurons against H2O2-induced oxidative stress.

BACKGROUND

Dorsal root ganglion (DRG) neurons are particularly susceptible to oxidative injury, which contributes to neuronal apoptosis and altered pain signaling. Oxidative stress in DRG neurons plays a pivotal role in the onset and maintenance of pain hypersensitivity under pathological conditions. We aimed to investigate the neuroprotective effects of Cibotii Rhizoma (CR) in rat DRG neurons subjected to H₂O₂-induced oxidative stress.

METHODS

Primary DRG neurons were isolated from 5-week-old Sprague–Dawley rats and cultured under short-term and long-term protocols. Cells were treated with CR (10–400 µg/mL) and exposed to H₂O₂. Cell viability was assessed by Cell Counting Kit-8 assay, and antioxidant effects were evaluated via DCFDA and MitoSOX-based flow cytometry and immunocytochemistry. Neurite outgrowth was analyzed using Tuj1 staining, and pain-related markers (CGRP, IB4, TRPV1, and substance P) were examined in long-term cultures. Molecular docking was performed to assess TRPV1 binding affinity of CR-derived compounds.

RESULTS

CR showed no cytotoxicity up to 400 µg/mL and significantly protected DRG neurons from 10 µg/mL against H2O2-induced oxidative stress. CR promoted neurite outgrowth and reduced oxidative stress markers (DCFDA⁺ and MitoSOX⁺ cells) within the 10–50 µg/mL concentration range, dose-dependently. Pain-related proteins (CGRP, IB4, TRPV1) and substance P were upregulated by H₂O₂ but significantly decreased following CR treatment. Molecular docking identified several CR-derived compounds with high binding affinity to TRPV1 may attenuate pain signaling pathways.

CONCLUSIONS

CR confers neuroprotection against oxidative stress in DRG neurons and modulates pain-related signaling pathways, highlighting its potential as a therapeutic agent for oxidative stress-induced neuropathic pain.