Stage-dependent analgesia of electro-acupuncture in a mouse model of cutaneous cancer pain.
Acupuncture is one of the most effective alternative medical treatments in pain management with the advantages of simple application, low cost and minimal side effects. However its scientific evidence and laws of action are not very clear in cancer pain relieving. The aim of this study was to examine the immediate and therapeutic anti-hyperalgesic effect of electro-acupuncture (EA) on a mouse model of cutaneous cancer pain. B16-BL6 melanoma cells were inoculated into the plantar region of unilateral hind paw and the thermal hyperalgesia was measured by using radiant heat test and hot plate test. C57BL/6 mice showed moderate and marked hyperalgesia during days 8-12 and from day 14 after the orthotopic inoculation of B16-BL6 melanoma cells into the hind paw. Single EA on day 8 after inoculation showed significant analgesic effect immediately after the treatment, the analgesic effect reached its maximum within 15-30min and declined to its minimum at 50min after EA treatment. Single EA treatment on day 20 showed no significant analgesic effect; Repeated EA treatments (started from day 8, once every other day) showed therapeutic analgesic effect, while it showed no therapeutic effect when started from day 16, a relatively late stage of this cancer pain model. The results demonstrated that EA had anti-hyperalgesic effect on early stage of cutaneous cancer pain but not on late stage. These results indicated a tight correlation of EA anti-hyperalgesic effects with the time window of cancer pain.
Mao-Ying
Qi-Liang
QL
Department of Integrative Medicine and Neurobiology, Institute of Acupuncture Research, Shanghai Medical College, Fudan University, Post Box 291, 138 Yi Xue Yuan Road, Shanghai 200032, China.
Cui
Ke-Mi
KM
Liu
Qiong
Q
Dong
Zhi-Qiang
ZQ
Wang
Wei
W
Wang
Jun
J
Sha
Hong
H
Wu
Gen-Cheng
GC
Wang
Yan-Qing
YQ
D000818:Animals; D004195:Disease Models, Animal; D015671:Electroacupuncture; D006358:Hot Temperature; D006930:Hyperalgesia / Q000209:etiology* / Q000628:therapy*; D008297:Male; D008545:Melanoma / Q000150:complications* / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D017288:Pain Threshold; D011930:Reaction Time; D012878:Skin Neoplasms / Q000150:complications* / Q000473:pathology; D013997:Time Factors