Yokukansan Improves Mechanical Allodynia through the Regulation of Interleukin-6 Expression in the Spinal Cord in Mice with Neuropathic Pain

Figure 4

Effects of yokukansan and the constituent herbal medicines on the expression of interleukin- (IL-) 6 mRNA in the spinal cord of mice with mechanical allodynia induced by partial sciatic nerve ligation (PSL). The total RNA of the L3–L6 level of the spinal cord of the ipsilateral posterior side was extracted 11 days after surgery. Expression of IL-6 mRNA in the spinal cord was determined using real time polymerase chain reaction. (a) The expression of IL-6 mRNA in the spinal cord of the sham (SHM) and PSL-treated mice. Yokukansan extract (YKS, 1 g/kg) (b), a mixture (MIX) of Glycyrrhizae Radix (GR, 100 mg/kg) and Atractylodis Lanceae Rhizoma (ALR, 200 mg/kg) extracts (c), ALR extract (200 mg/kg) (d), GR extract (100 mg/kg) (e), or vehicle (VH) was orally administered once a day from day 4 after surgery for 7 days. Expression of IL-6 mRNA in each sample was normalized to that of glyceraldehyde-3-phosphate dehydrogenase, followed by normalization to its expression level in the controls. The upper right panel shows the site of evaluation of IL-6 mRNA expression. Data are presented as means ± standard errors of the means (). , compared with the sham mice or VH-treated mice (Student’s -test).

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