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Pulsed Radiofrequency Applied to the Sciatic Nerve Improves Neuropathic Pain by Down-regulating The Expression of Calcitonin Gene-related Peptide in the Dorsal Root Ganglion.
Int J Med Sci. 2018; 15(2):153-160.IJ

Abstract

Background:

Clinical studies have shown that applying pulsed radiofrequency (PRF) to the neural stem could relieve neuropathic pain (NP), albeit through an unclear analgesic mechanism. And animal experiments have indicated that calcitonin gene-related peptide (CGRP) expressed in the dorsal root ganglion (DRG) is involved in generating and maintaining NP. In this case, it is uncertain whether PRF plays an analgesic role by affecting CGRP expression in DRG.

Methods:

Rats were randomly divided into four groups: Groups A, B, C, and D. In Groups C and D, the right sciatic nerve was ligated to establish the CCI model, while in Groups A and B, the sciatic nerve was isolated without ligation. After 14 days, the right sciatic nerve in Groups B and D re-exposed and was treated with PRF on the ligation site. Thermal withdrawal latency (TWL) and hindpaw withdrawal threshold (HWT) were measured before PRF treatment (Day 0) as well as after 2, 4, 8, and 14 days of treatment. At the same time points of the behavioral tests, the right L4-L6 DRG was sampled and analyzed for CGRP expression using RT-qPCR and an enzyme-linked immunosorbent assay (ELISA).

Results:

Fourteen days after sciatic nerve ligation, rats in Groups C and D had a shortened TWL (P<0.001) and a reduced HWT (P<0.001) compared to those in Groups A and B. After PRF treatment, the TWL of the rats in Group D gradually extended with HWT increasing progressively. Prior to PRF treatment (Day 0), CGRP mRNA expressions in the L4-L6 DRG of Groups C and D increased significantly (P<0.001) and were 2.7 and 2.6 times that of Group A respectively. ELISA results showed that the CGRP content of Groups C and D significantly increased in comparison with that of Groups A and B (P<0.01). After PRF treatment, the mRNA expression in the DRG of Group D gradually decreased and the mRNA expression was 1.7 times that of Group A on the 4th day(P> 0.05). On the 8th and 14th days, the mRNA levels in Group D were restored to those of Groups A and B. Meanwhile, the CGRP content of Group D gradually dropped over time, from 76.4 pg/mg (Day 0) to 57.5 pg/mg (Day 14).

Conclusions:

In this study, we found that, after sciatic nerve ligation, rats exhibited apparent hyperalgesia and allodynia, and CGRP mRNA and CGRP contents in the L4-L6 DRG increased significantly. Through lowering CGRP expression in the DRG, PRF treatment might relieve the pain behaviors of NP.

Authors+Show Affiliations

Department of Anesthesiology and Pain Management, Beijing Tiantan Hospital, Capital Medical University.Department of Anesthesiology and Pain Management, Beijing Tiantan Hospital, Capital Medical University.Department of Anesthesiology and Pain Management, Beijing Tiantan Hospital, Capital Medical University.Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University.Department of Anesthesiology and Pain Management, Beijing Tiantan Hospital, Capital Medical University.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

29333099

Citation

Ren, Hao, et al. "Pulsed Radiofrequency Applied to the Sciatic Nerve Improves Neuropathic Pain By Down-regulating the Expression of Calcitonin Gene-related Peptide in the Dorsal Root Ganglion." International Journal of Medical Sciences, vol. 15, no. 2, 2018, pp. 153-160.
Ren H, Jin H, Jia Z, et al. Pulsed Radiofrequency Applied to the Sciatic Nerve Improves Neuropathic Pain by Down-regulating The Expression of Calcitonin Gene-related Peptide in the Dorsal Root Ganglion. Int J Med Sci. 2018;15(2):153-160.
Ren, H., Jin, H., Jia, Z., Ji, N., & Luo, F. (2018). Pulsed Radiofrequency Applied to the Sciatic Nerve Improves Neuropathic Pain by Down-regulating The Expression of Calcitonin Gene-related Peptide in the Dorsal Root Ganglion. International Journal of Medical Sciences, 15(2), 153-160. https://doi.org/10.7150/ijms.20501
Ren H, et al. Pulsed Radiofrequency Applied to the Sciatic Nerve Improves Neuropathic Pain By Down-regulating the Expression of Calcitonin Gene-related Peptide in the Dorsal Root Ganglion. Int J Med Sci. 2018;15(2):153-160. PubMed PMID: 29333099.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Pulsed Radiofrequency Applied to the Sciatic Nerve Improves Neuropathic Pain by Down-regulating The Expression of Calcitonin Gene-related Peptide in the Dorsal Root Ganglion. AU - Ren,Hao, AU - Jin,Hailong, AU - Jia,Zipu, AU - Ji,Nan, AU - Luo,Fang, Y1 - 2018/01/01/ PY - 2017/04/10/received PY - 2017/07/06/accepted PY - 2018/1/16/entrez PY - 2018/1/16/pubmed PY - 2018/8/22/medline KW - Neuropathic pain KW - analgesia KW - calcitonin gene-related peptide KW - chronic constriction injury KW - dorsal root ganglion KW - pulsed radiofrequency SP - 153 EP - 160 JF - International journal of medical sciences JO - Int J Med Sci VL - 15 IS - 2 N2 - Background: Clinical studies have shown that applying pulsed radiofrequency (PRF) to the neural stem could relieve neuropathic pain (NP), albeit through an unclear analgesic mechanism. And animal experiments have indicated that calcitonin gene-related peptide (CGRP) expressed in the dorsal root ganglion (DRG) is involved in generating and maintaining NP. In this case, it is uncertain whether PRF plays an analgesic role by affecting CGRP expression in DRG. Methods: Rats were randomly divided into four groups: Groups A, B, C, and D. In Groups C and D, the right sciatic nerve was ligated to establish the CCI model, while in Groups A and B, the sciatic nerve was isolated without ligation. After 14 days, the right sciatic nerve in Groups B and D re-exposed and was treated with PRF on the ligation site. Thermal withdrawal latency (TWL) and hindpaw withdrawal threshold (HWT) were measured before PRF treatment (Day 0) as well as after 2, 4, 8, and 14 days of treatment. At the same time points of the behavioral tests, the right L4-L6 DRG was sampled and analyzed for CGRP expression using RT-qPCR and an enzyme-linked immunosorbent assay (ELISA). Results: Fourteen days after sciatic nerve ligation, rats in Groups C and D had a shortened TWL (P<0.001) and a reduced HWT (P<0.001) compared to those in Groups A and B. After PRF treatment, the TWL of the rats in Group D gradually extended with HWT increasing progressively. Prior to PRF treatment (Day 0), CGRP mRNA expressions in the L4-L6 DRG of Groups C and D increased significantly (P<0.001) and were 2.7 and 2.6 times that of Group A respectively. ELISA results showed that the CGRP content of Groups C and D significantly increased in comparison with that of Groups A and B (P<0.01). After PRF treatment, the mRNA expression in the DRG of Group D gradually decreased and the mRNA expression was 1.7 times that of Group A on the 4th day(P> 0.05). On the 8th and 14th days, the mRNA levels in Group D were restored to those of Groups A and B. Meanwhile, the CGRP content of Group D gradually dropped over time, from 76.4 pg/mg (Day 0) to 57.5 pg/mg (Day 14). Conclusions: In this study, we found that, after sciatic nerve ligation, rats exhibited apparent hyperalgesia and allodynia, and CGRP mRNA and CGRP contents in the L4-L6 DRG increased significantly. Through lowering CGRP expression in the DRG, PRF treatment might relieve the pain behaviors of NP. SN - 1449-1907 UR - https://www.unboundmedicine.com/medline/citation/29333099/Pulsed_Radiofrequency_Applied_to_the_Sciatic_Nerve_Improves_Neuropathic_Pain_by_Down_regulating_The_Expression_of_Calcitonin_Gene_related_Peptide_in_the_Dorsal_Root_Ganglion_ L2 - https://www.medsci.org/v15p0153.htm DB - PRIME DP - Unbound Medicine ER -