Intrathecal Injection of （-）-Epigallocatechin Gallate （EGCG） Alleviates Chronic Primary Pain Induced by High-frequency Stimulation in Female Mice
10.13471/j.cnki.j.sun.yat-sen.univ（med.sci）.2022.0207
- VernacularTitle:表没食子儿茶素没食子酸酯缓解高频刺激诱导的雌性小鼠慢性原发性疼痛
- Author:
Yuan TANG
1
;
Dong-mei JIN
2
;
Ying-tao JIE
1
;
Zhen-jia LIN
1
;
Ying XIONG
1
;
Xiang-ge PENG
1
;
Li-jun ZHOU
1
;
Zhi TAN
1
Author Information
1. Department of Physiology， Zhongshan School of Medical， Sun Yat-sen University， and Center for Pain Research， Sun Yat-sen University， Guangzhou 510080， China
2. Department of Rehabilitation Medicine， Sun Yat-sen Memorial Hospital， Sun Yat-sen University， Guangzhou， 510120， China
- Publication Type:Journal Article
- Keywords:
chronic primary pain;
（-）-epigallocatechin gallate;
high-frequency stimulation;
c-Fos;
calcitonin gene-related peptide （CGRP）
- From:
Journal of Sun Yat-sen University(Medical Sciences)
2022;43(2):221-228
- CountryChina
- Language:Chinese
-
Abstract:
ObjectiveTo investigate the analgesic effect and its mechanism of （-）-gallocatechin gallate （EGCG） on high-frequency stimulation （HFS）-induced chronic primary pain in female mice. MethodsThe model of chronic primary pain in female mice were established by HFS of sciatic nerve in left hind limb at 10 V （100 Hz， 0.5 ms， 4 trains of 1-s duration at 10-s intervals）. The mice were randomly divided into sham operation group， vehicle （saline） + HFS group， different concentrations of EGCG + HFS groups （4~5 mice in each group）. 10 μL EGCG （10， 20， 50， 200 μmol/L） or vehicle was injected intrathecally 1 h before surgery. The therapeutic effect of EGCG was evaluated by paw withdrawal threshold （PWT） and analgesic efficiency. Immunofluorescence of lumbar spinal cord was used to evaluate the possible mechanisms. ResultsCompared with vehicle HFS group， intrathecal administration of EGCG alleviated HFS-induced mechanical allodynia in a dose-dependent manner， and the maximum analgesic efficiency was 84.95%. EGCG also blocked the increases in c-Fos （a marker for neuronal excitability） positive neurons and the expressions of calcitonin gene-related peptide （CGRP+） terminals， Iba1 （a marker for microglia） and GFAP （a marker for astrocytes） in the ipsilateral spinal dorsal horn. ConclusionIntrathecal injection of EGCG exerts an analgesic effect against HFS-induced chronic primary pain， mediated by inhibiting the increases in presynaptic CGRP+ terminals， postsynaptic neuronal excitability and glial activation in the spinal dorsal horn.
