Abstract
Ethnopharmacological relevance
Chronic migraine is a recurrent throbbing headache, which is often attributed to stagnated Qi and impaired blood circulation from the perspective of traditional Chinese medicine. Xiongfu formula (CRCR), consisting of Chuanxiong Rhizoma and Cyperi Rhizoma, is a classic herbal formula in treating migraine from the treatise Jingyue Quanshu during the Ming Dynasty.Aim of the study
This study sought to look at the potential molecular mechanism of CRCR and its active constituents for chronic migraine therapy.Methods
A rat model of chronic migraine was established by dural infusion of inflammatory soup. Pain-related behavioral assessments and trigeminal nerve injuries were used to evaluate CRCR's efficacy in chronic migraine treatment. RNA-seq, RT-qPCR, western blotting and immunofluorescence assays were applied to identify the potential signaling pathways. The components of CRCR in the blood and brain tissues of chronic migraine rats were quantitatively determined using UPLC-MS/MS. The active ingredient against neuroinflammation in chronic migraine was further validated in BV-2 cell model.Results
CRCR increased mechanical and thermal pain thresholds and inhibited the central sensitization in chronic migraine rats, suggesting its therapeutic ability in alleviating pain hypersensitivity and trigeminal nerve injuries. Transcriptomic analysis indicated the MAPK signaling pathway as the potential therapeutic target. CRCR suppressed MAPK pathway by downregulating MEK, ERK, JNK, p38, CREB and downstream effectors. CRCR also inhibited neuroinflammation by modulating microglial activation and decreasing inflammatory cytokines. Spectrum-effect correlation analysis and experimental validation reveled that Z-ligustilide (LIG) is the most promising active ingredient in CRCR for inhibiting neuroinflammation. Especially, the levels of LIG metabolites were below the limit of detection and were therefore not detected, while the parent molecular of LIG presents a high level in rat brain. Further verification demonstrated that LIG alleviated neuroinflammation via inhibiting MAPK/CREB and MEK/ERK pathway. And LIG had a stronger effect on the inflammatory factors compared to the reference inhibitor U0126.Conclusions
CRCR provided therapeutic benefits against chronic migraine through regulating the MAPK/ERK/CREB pathway. LIG represents a higher content in the blood and brain of migraine rats and remarkably suppresses MAPK/ERK/CREB pathway. Targeting MAPK mediated neuroinflammation with LIG and CRCR could serve as a potential treatment option for neuroinflammatory illnesses such as chronic migraine in future.