Research Paper Volume 12, Issue 9 pp 7945—7962
Osthole alleviates neuropathic pain in mice by inhibiting the P2Y1-receptor-dependent JNK signaling pathway
- 1 Department of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
- 2 Department of Anesthesiology, Shaanxi Provincial Cancer Hospital, Xi’an, Shaanxi 71061, China
Received: November 28, 2019 Accepted: April 11, 2020 Published: May 4, 2020https://doi.org/10.18632/aging.103114
How to Cite
Copyright © 2020 Li et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
There are many reports about natural products relieving neuralgia. Osthole is the main component of Angelica biserrata Yuan et Shan, a natural product that treats rheumatism through the elimination of inflammation and the alleviation of pain that has a long history in the clinic. The analgesic mechanism of osthole is complicated and confusing. Astrocytes have attracted increasing attention from pain researchers. Inhibitors targeting astrocytes are thought to be promising treatments for neuropathic pain. Whether osthole can alleviate neuropathic pain through astrocytes has not been elucidated in detail. In this study, CCI surgery was used to establish the neuropathic pain model in mice. The CCI mice were treated with osthole (5, 10, or 20 mg/kg/day) for 14 days in vivo. Mechanical allodynia and heat hyperalgesia were measured to evaluate the therapeutic effect of osthole. In mechanism research, the activation of astrocytes; the protein expression of P2Y1R and p-JNK in astrocytes; the release of inflammatory factors; the variations in mEPSPs and eEPSPs; and the levels of GluA1, GluN2B, p-ERK, p-CREB and c-Fos in neurons were observed. The P2Y1R inhibitor MRS2179 and the p-JNK inhibitor SP600125 were used to demonstrate how osthole works in neuropathic pain. In addition, astrocytes and neurons were used to estimate the direct effect of osthole on astrocyte-neuron interactions and signal transmission in vitro. Our findings suggest that osthole treatment obviously relieved mechanical allodynia and heat hyperalgesia in CCI mice. P2Y1R is involved in CCI-induced pain hypersensitivity, and P2Y1R is required for osthole-induced p-JNK downregulation in the spinal cord. Osthole inhibited astrocyte activation and reduced inflammatory factor expression. After osthole treatment, mEPSP frequency and eEPSP amplitude were decreased in spinal lamina I-II neurons. Downstream signaling molecules such as pGluA1, pGluN2B, p-ERK, p-CREB and c-Fos were also reduced very quickly in osthole-treated neuralgic mice. Our conclusion is that osthole alleviates neuropathic pain in mice via the P2Y1-receptor-dependent JNK signaling pathway in spinal astrocytes, and osthole could be considered a potential pharmacotherapy to alleviate neuropathic pain.
CCI: chronic constriction injury; JNK: c-Jun N-terminal kinase; NMDA: N-methyl-D-aspartic acid receptor; AMPA: α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor; p-ERK: phosphorylated extracellular signal regulated kinase; p-CREB: phosphorylated cAMP-response element binding protein; mEPSP: Miniature evoke excitatory postsynaptic potential; MAPK: mitogen-activated protein kinase; GFAP: glial fibrillary acidic protein; PBS: phosphate buffer saline; TNF-α: Tumor necrosis factor-α; IL-1β: Interleukin 1β; IL-6: Interleukin 6; PWL: paw withdrawal latency; PWT: paw withdrawal threshold.