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Effect of Repeated Electroacupuncture Intervention on Hippocampal ERK and p38MAPK Signaling in Neuropathic Pain Rats.

Wang JY, Chen SP, Gao YH, Qiao LN, Zhang JL, Liu JL - Evid Based Complement Alternat Med (2015)

Bottom Line: After CCI, the thermal pain thresholds of the affected hind were significantly decreased compared with the control group (P < 0.05).Following one and two weeks' EAS of ST 36-GB34, the pain thresholds were significantly upregulated (P < 0.05), and the effect of EA2W was remarkably superior to that of EA2D and EA1W (P < 0.05).The above mentioned results indicated that EA2W induced cumulative analgesic effect may be closely associated with its function in removing neuropathic pain induced suppression of intracellular ERK and p38MAPK signaling in the hippocampus.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China.

ABSTRACT
Results of our past studies showed that hippocampal muscarinic acetylcholine receptor (mAChR)-1 mRNA and differentially expressed proteins participating in MAPK signaling were involved in electroacupuncture (EA) induced cumulative analgesia in neuropathic pain rats, but the underlying intracellular mechanism remains unknown. The present study was designed to observe the effect of EA stimulation (EAS) on hippocampal extracellular signal-regulated kinases (ERK) and p38 MAPK signaling in rats with chronic constrictive injury (CCI) of the sciatic nerve, so as to reveal its related intracellular targets in pain relief. After CCI, the thermal pain thresholds of the affected hind were significantly decreased compared with the control group (P < 0.05). Following one and two weeks' EAS of ST 36-GB34, the pain thresholds were significantly upregulated (P < 0.05), and the effect of EA2W was remarkably superior to that of EA2D and EA1W (P < 0.05). Correspondingly, CCI-induced decreased expression levels of Ras, c-Raf, ERK1 and p-ERK1/2 proteins, and p38 MAPK mRNA and p-p38MAPK protein in the hippocampus tissues were reversed by EA2W (P < 0.05). The above mentioned results indicated that EA2W induced cumulative analgesic effect may be closely associated with its function in removing neuropathic pain induced suppression of intracellular ERK and p38MAPK signaling in the hippocampus.

No MeSH data available.


Related in: MedlinePlus

Effect of EA on expression levels of hippocampal ERK1/2mRNA and ERK1/2 and p- ERK1/2 protein in different groups. Hippocampal ERK1/2mRNA expression levels were assessed by real-time PCR and ERK1/2 protein expressions were detected by Western blot. Data are presented as mean ± SD (∗P < 0.05, compared with the sham control group; ☆P < 0.05, compared with the CCI group; n = 6 in each group for real-time PCR; n = 5 for each group for western blot); (a) histograms show the expression levels of ERK1/2 mRNA. (b) The top panel shows the representative immunoblots of ERK1/2 proteins in the 5 groups: (1) sham control group, (2) CCI group, (3) CCI + EA2D group, (4) CCI + EA1W group, and (5) CCI + EA2W group. The histograms show relative expression levels of ERK1/2 proteins in the 5 groups. (c) The upper panel shows the representative immunoblots of p-ERK1/2 proteins in the 5 groups. The lower bar graph shows the relative expression of p-ERK1/2 proteins in the 5 groups.
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fig4: Effect of EA on expression levels of hippocampal ERK1/2mRNA and ERK1/2 and p- ERK1/2 protein in different groups. Hippocampal ERK1/2mRNA expression levels were assessed by real-time PCR and ERK1/2 protein expressions were detected by Western blot. Data are presented as mean ± SD (∗P < 0.05, compared with the sham control group; ☆P < 0.05, compared with the CCI group; n = 6 in each group for real-time PCR; n = 5 for each group for western blot); (a) histograms show the expression levels of ERK1/2 mRNA. (b) The top panel shows the representative immunoblots of ERK1/2 proteins in the 5 groups: (1) sham control group, (2) CCI group, (3) CCI + EA2D group, (4) CCI + EA1W group, and (5) CCI + EA2W group. The histograms show relative expression levels of ERK1/2 proteins in the 5 groups. (c) The upper panel shows the representative immunoblots of p-ERK1/2 proteins in the 5 groups. The lower bar graph shows the relative expression of p-ERK1/2 proteins in the 5 groups.

Mentions: Like MEK, ERK exists in two isoforms (1 and 2). In order to identify changes of hippocampal ERK1/2 in both mRNA and protein expression levels, we conducted real-time PCR and Western blot measurements. Compared with the control group, the expression levels of hippocampal ERK1/2mRNA and ERK1/2 protein in the CCI group had no significant changes (P > 0.05), except for a marked upregulation of ERK1 protein expression in the CCI + EA2W group in comparison with the CCI group (P < 0.05, Figures 4(a) and 4(b)). Further tests revealed that the relative expression of p-ERK1/2 protein was considerably downregulated in the CCI group compared with the control group (P < 0.05, Figure 4(c)) and obviously upregulated in the CCI + EA2D, CCI + EA1W, and CCI + EA2W groups after EAS (P < 0.05). There was no significant difference among the three EAS groups in hippocampal p-ERK1/2 protein expression levels (P > 0.05, Figure 4(c)).


Effect of Repeated Electroacupuncture Intervention on Hippocampal ERK and p38MAPK Signaling in Neuropathic Pain Rats.

Wang JY, Chen SP, Gao YH, Qiao LN, Zhang JL, Liu JL - Evid Based Complement Alternat Med (2015)

Effect of EA on expression levels of hippocampal ERK1/2mRNA and ERK1/2 and p- ERK1/2 protein in different groups. Hippocampal ERK1/2mRNA expression levels were assessed by real-time PCR and ERK1/2 protein expressions were detected by Western blot. Data are presented as mean ± SD (∗P < 0.05, compared with the sham control group; ☆P < 0.05, compared with the CCI group; n = 6 in each group for real-time PCR; n = 5 for each group for western blot); (a) histograms show the expression levels of ERK1/2 mRNA. (b) The top panel shows the representative immunoblots of ERK1/2 proteins in the 5 groups: (1) sham control group, (2) CCI group, (3) CCI + EA2D group, (4) CCI + EA1W group, and (5) CCI + EA2W group. The histograms show relative expression levels of ERK1/2 proteins in the 5 groups. (c) The upper panel shows the representative immunoblots of p-ERK1/2 proteins in the 5 groups. The lower bar graph shows the relative expression of p-ERK1/2 proteins in the 5 groups.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig4: Effect of EA on expression levels of hippocampal ERK1/2mRNA and ERK1/2 and p- ERK1/2 protein in different groups. Hippocampal ERK1/2mRNA expression levels were assessed by real-time PCR and ERK1/2 protein expressions were detected by Western blot. Data are presented as mean ± SD (∗P < 0.05, compared with the sham control group; ☆P < 0.05, compared with the CCI group; n = 6 in each group for real-time PCR; n = 5 for each group for western blot); (a) histograms show the expression levels of ERK1/2 mRNA. (b) The top panel shows the representative immunoblots of ERK1/2 proteins in the 5 groups: (1) sham control group, (2) CCI group, (3) CCI + EA2D group, (4) CCI + EA1W group, and (5) CCI + EA2W group. The histograms show relative expression levels of ERK1/2 proteins in the 5 groups. (c) The upper panel shows the representative immunoblots of p-ERK1/2 proteins in the 5 groups. The lower bar graph shows the relative expression of p-ERK1/2 proteins in the 5 groups.
Mentions: Like MEK, ERK exists in two isoforms (1 and 2). In order to identify changes of hippocampal ERK1/2 in both mRNA and protein expression levels, we conducted real-time PCR and Western blot measurements. Compared with the control group, the expression levels of hippocampal ERK1/2mRNA and ERK1/2 protein in the CCI group had no significant changes (P > 0.05), except for a marked upregulation of ERK1 protein expression in the CCI + EA2W group in comparison with the CCI group (P < 0.05, Figures 4(a) and 4(b)). Further tests revealed that the relative expression of p-ERK1/2 protein was considerably downregulated in the CCI group compared with the control group (P < 0.05, Figure 4(c)) and obviously upregulated in the CCI + EA2D, CCI + EA1W, and CCI + EA2W groups after EAS (P < 0.05). There was no significant difference among the three EAS groups in hippocampal p-ERK1/2 protein expression levels (P > 0.05, Figure 4(c)).

Bottom Line: After CCI, the thermal pain thresholds of the affected hind were significantly decreased compared with the control group (P < 0.05).Following one and two weeks' EAS of ST 36-GB34, the pain thresholds were significantly upregulated (P < 0.05), and the effect of EA2W was remarkably superior to that of EA2D and EA1W (P < 0.05).The above mentioned results indicated that EA2W induced cumulative analgesic effect may be closely associated with its function in removing neuropathic pain induced suppression of intracellular ERK and p38MAPK signaling in the hippocampus.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China.

ABSTRACT
Results of our past studies showed that hippocampal muscarinic acetylcholine receptor (mAChR)-1 mRNA and differentially expressed proteins participating in MAPK signaling were involved in electroacupuncture (EA) induced cumulative analgesia in neuropathic pain rats, but the underlying intracellular mechanism remains unknown. The present study was designed to observe the effect of EA stimulation (EAS) on hippocampal extracellular signal-regulated kinases (ERK) and p38 MAPK signaling in rats with chronic constrictive injury (CCI) of the sciatic nerve, so as to reveal its related intracellular targets in pain relief. After CCI, the thermal pain thresholds of the affected hind were significantly decreased compared with the control group (P < 0.05). Following one and two weeks' EAS of ST 36-GB34, the pain thresholds were significantly upregulated (P < 0.05), and the effect of EA2W was remarkably superior to that of EA2D and EA1W (P < 0.05). Correspondingly, CCI-induced decreased expression levels of Ras, c-Raf, ERK1 and p-ERK1/2 proteins, and p38 MAPK mRNA and p-p38MAPK protein in the hippocampus tissues were reversed by EA2W (P < 0.05). The above mentioned results indicated that EA2W induced cumulative analgesic effect may be closely associated with its function in removing neuropathic pain induced suppression of intracellular ERK and p38MAPK signaling in the hippocampus.

No MeSH data available.


Related in: MedlinePlus