Transcranial direct current stimulation for the relief of neuropathic pain in rats and the underlying mechanism
10.3760/cma.j.issn.0254-1424.2022.04.005
- VernacularTitle:重复经颅直流电刺激治疗神经病理性疼痛的效果观察及机制初探
- Author:
Bingbing LI
1
;
Tao XU
;
Shengjie WANG
;
Ting JIANG
;
Lu LIU
;
Limei WANG
Author Information
1. 华中科技大学同济医学院附属同济医院康复医学科，武汉 430030
- Keywords:
Neuropathic pain;
Transcranial direct current stimulation;
N-methyl-D-aspartate receptor;
Gamma-aminobutyric acid receptor
- From:
Chinese Journal of Physical Medicine and Rehabilitation
2022;44(4):312-317
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To observe any therapeutic effect of repeated transcranial direct current stimulation (tDCS) on rats modeling neuropathic pain and explore possible mechanisms.Methods:Forty adult male Sprague-Dawley rats were randomly divided into a normal group ( n=10), a sham operation group ( n=10), a treatment group ( n=10) and a sham treatment group ( n=10). A model of chronic constriction injury of the sciatic nerve was established in the latter two groups. Fourteen days after the modeling, the treatment group was given tDCS for 8 consecutive days, while the sham treatment group received sham stimulation, and the other 2 groups did not receive any intervention. Von Frey and hotplate tests were used to test the rats′ pain thresholds 1 day before, as well as 14 and 22 days after the surgery (i.e., 8 days after the end of the treatment). Spinal cord tissue samples were taken to detect the protein expressions of N-methyl-D-aspartic acid receptor 2B, gamma-aminobutyric acid receptor types A (GABA a-R) and B (GABA b-R) using western blotting. Results:On the 14th day after the operation the average 50% MWT and WTL values of the sham treatment and treatment groups had decreased significantly compared with the sham operation group. By the 22nd day the average 50% MWT and WTL values of the treatment group were significantly higher than those of the sham treatment group, but there was no significant change in the treatment group′s average WTL between the 21st and 22nd days. On the 22nd day after the operation the average NR2B-NMDA-R level of the sham treatment group were significantly higher than that of the sham operation group, while the average GABA a-R and GABA b-R levels were significantly lower. At the same time point the treatment group′s average NR2B-NMDA-R level had decreased significantly compared to the sham treatment group, while the average GABA a-R level had increased significantly. There was no significant difference in average GABA b-R level between the treatment group and the sham treatment group at that point. On the 22nd day there was also no significant difference in the average NR2B-NMDA-R level between the treatment group and the sham operation group. Conclusions:Repeated tDCS can effectively relieve neuropathic pain. The relief of hyperalgesia is more significant than that of mechanical allodynia. A possible mechanism may be the down-regulation of spinal NR2B-NMDA-R to normal levels and modest up-regulation of GABA a-R.
