TY - JOUR
T1 - Chronic electrical stimulation reduces hyperalgesia and associated spinal changes induced by peripheral nerve injury
AU - López-Álvarez, Víctor M.
AU - Cobianchi, Stefano
AU - Navarro, Xavier
PY - 2019/7/1
Y1 - 2019/7/1
N2 - © 2019 International Neuromodulation Society Objectives: We aimed to investigate if different protocols of electrical stimulation following nerve injury might improve neuropathic pain outcomes and modify associated plastic changes at the spinal cord level. Materials and Methods: Adult rats were subjected to sciatic nerve transection and repair, and distributed in four groups: untreated (SNTR, n = 12), repeated acute electrical stimulation (rAES, 50 Hz, one hour, n = 12), chronic electrical stimulation (CES, 50 Hz, one hour, n = 12), and increasing-frequency chronic electrical stimulation (iCES, one hour, n = 12) delivered during two weeks following the lesion. The threshold of nociceptive withdrawal to mechanical stimuli was evaluated by means of a Von Frey algesimeter during three weeks postlesion. Spinal cord samples were processed by immunohistochemistry for labeling glial cells, adrenergic receptors, K+-Cl− cotransporter 2 (KCC2) and GABA. Results: Acute electrical stimulation (50 Hz, one hour) delivered at 3, 7, and 14 days induced an immediate increase of mechanical pain threshold that disappeared after a few days. Chronic electrical stimulation given daily reduced mechanical hyperalgesia until the end of follow-up, being more sustained with the iCES than with constant 50 Hz stimulation (CES). Chronic stimulation protocols restored the expression of β2 adrenergic receptor and of KCC2 in the dorsal horn, which were significantly reduced by nerve injury. These treatments decreased also the activation of microglia and astrocytes in the dorsal horn. Conclusion: Daily electrical stimulation, especially if frequency-patterned, was effective in ameliorating hyperalgesia after nerve injury, and partially preventing the proinflammatory and hyperalgesic changes in the dorsal horn associated to neuropathic pain.
AB - © 2019 International Neuromodulation Society Objectives: We aimed to investigate if different protocols of electrical stimulation following nerve injury might improve neuropathic pain outcomes and modify associated plastic changes at the spinal cord level. Materials and Methods: Adult rats were subjected to sciatic nerve transection and repair, and distributed in four groups: untreated (SNTR, n = 12), repeated acute electrical stimulation (rAES, 50 Hz, one hour, n = 12), chronic electrical stimulation (CES, 50 Hz, one hour, n = 12), and increasing-frequency chronic electrical stimulation (iCES, one hour, n = 12) delivered during two weeks following the lesion. The threshold of nociceptive withdrawal to mechanical stimuli was evaluated by means of a Von Frey algesimeter during three weeks postlesion. Spinal cord samples were processed by immunohistochemistry for labeling glial cells, adrenergic receptors, K+-Cl− cotransporter 2 (KCC2) and GABA. Results: Acute electrical stimulation (50 Hz, one hour) delivered at 3, 7, and 14 days induced an immediate increase of mechanical pain threshold that disappeared after a few days. Chronic electrical stimulation given daily reduced mechanical hyperalgesia until the end of follow-up, being more sustained with the iCES than with constant 50 Hz stimulation (CES). Chronic stimulation protocols restored the expression of β2 adrenergic receptor and of KCC2 in the dorsal horn, which were significantly reduced by nerve injury. These treatments decreased also the activation of microglia and astrocytes in the dorsal horn. Conclusion: Daily electrical stimulation, especially if frequency-patterned, was effective in ameliorating hyperalgesia after nerve injury, and partially preventing the proinflammatory and hyperalgesic changes in the dorsal horn associated to neuropathic pain.
KW - Electrical stimulation
KW - hyperalgesia
KW - neuropathic pain
KW - sciatic nerve
KW - spinal cord
U2 - https://doi.org/10.1111/ner.12927
DO - https://doi.org/10.1111/ner.12927
M3 - Article
C2 - 30786105
VL - 22
SP - 509
EP - 518
JO - Neuromodulation
JF - Neuromodulation
SN - 1094-7159
ER -