Berbamine Alleviates Chronic Inflammatory Pain via Microglial Inhibition and Oxidative Stress Reduction in the Anterior Cingulate Cortex.
Qin Yan, Yao Jingyue, Wang Yuhua, Wang Linxi, Chen Yue, Wang Qinhui, Wang Saiying, Rong Zheng, Luo Li, Wu Yumei, Yang Yang, Guan Feng, Gao Ying, Zhao Minggao, Yang Le
Abstract
Chronic pain, defined as persistent pain lasting beyond three months, imposes a severe burden on patient quality of life. Berbamine (BBM), a natural bisbenzylisoquinoline alkaloid with anti-inflammatory and antioxidant properties, is a promising candidate for pain management, although its analgesic mechanism remains unclear. This study investigated the efficacy and mechanism of BBM in a complete Freund's adjuvant-induced mouse model of chronic inflammatory pain. Behavioral testing revealed that BBM significantly increased mechanical and thermal pain thresholds, indicating its effective antinociceptive action. Histological and biochemical analyses showed that BBM inhibited microglial activation in the anterior cingulate cortex (ACC), reduced proinflammatory cytokines, activated the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, increased the expression of the Nrf2-driven antioxidant proteins heme oxygenase-1 (HO-1) and glutathione peroxidase 4 (GPX4), decreased malondialdehyde (MDA) levels, and enhanced superoxide dismutase (SOD) activity, indicating attenuation of oxidative stress. In lipopolysaccharide (LPS)-stimulated BV2 microglial cells, BBM similarly reduced inflammatory cytokine production, reactive oxygen species, and mitochondrial superoxide while preserving mitochondrial membrane potential and restoring redox balance. Consistent with the in vivo findings, BBM activated Nrf2, thereby promoting the mRNA expression of downstream antioxidants, such as NAD(P)H quinone oxidoreductase 1 (NQO1), HO-1, and SOD. At the protein level, BBM simultaneously upregulated HO-1 and GPX4, suppressed the phosphorylation of nuclear factor kappa-B (NF-κB) p65, and decreased Kelch-like ECH-associated protein 1 (KEAP1) abundance to sustain Nrf2 activation. Collectively, our findings reveal that BBM alleviates chronic inflammatory pain via dual anti-inflammatory and antioxidant effects: it suppresses ACC microglial overactivation to block NF-κB-mediated neuroinflammation, while reducing KEAP1 levels to sustain Nrf2 signaling, thereby increasing antioxidant proteins HO-1, GPX4 and NQO1 transcript levels to mitigate central oxidative stress.
Key Findings
- Berbamine (BBM) significantly increased mechanical and thermal pain thresholds in a mouse model of chronic inflammatory pain, indicating effective antinociceptive action.
- BBM inhibited microglial activation in the anterior cingulate cortex (ACC) and reduced proinflammatory cytokines.
- BBM activated the Nrf2 pathway, increasing antioxidant proteins HO-1 and GPX4, reducing oxidative stress markers like MDA, and enhancing SOD activity.
- In LPS-stimulated BV2 microglial cells, BBM reduced inflammatory cytokine production, reactive oxygen species, and mitochondrial superoxide while preserving mitochondrial membrane potential.
- BBM suppressed NF-κB p65 phosphorylation and decreased KEAP1 abundance to sustain Nrf2 activation, promoting antioxidant gene expression.
Clinical Significance
Berbamine shows potential as a therapeutic agent for chronic inflammatory pain by targeting oxidative stress and neuroinflammation pathways, highlighting its promise for improving pain management through antioxidant and anti-inflammatory mechanisms.
Citation
Qin Yan, Yao Jingyue, Wang Yuhuaet al.. Berbamine Alleviates Chronic Inflammatory Pain via Microglial Inhibition and Oxidative Stress Reduction in the Anterior Cingulate Cortex. European journal of pharmacology. 2026-Sep-18.