Laboratory / Animal / Preclinical Studies
A rat model has been established by injecting AT-3.1 prostate cancer cells into the tibia of the adult male Copenhagen rat, which closely mimics prostate cancer-induced bone cancer pain. The cancer-caused pain was treated with 10 Hz EA for 30 minutes a day at acupuncture point gallbladder 30 (GB30) from days 14 to 18 after cancer-cell injection. For sham control, EA needles were inserted into GB30 without stimulation. Thermal hyperalgesia, a decrease in paw withdrawal latency to a noxious thermal stimulus, and mechanical hyperalgesia, a decrease in paw withdrawal pressure threshold, were measured at baseline and 20 minutes after EA. EA significantly attenuated the hyperalgesia compared with sham control. Moreover, the EA inhibited up-regulation of preprodynorphin mRNA and dynorphin as well as interleukin-1beta (IL-1beta) and its mRNA compared with sham control. Intrathecal injection of antiserum against dynorphin A (1–17) and IL-1 receptor antagonist significantly inhibited the cancer-induced hyperalgesia. These data suggests that EA alleviates bone cancer pain at least in part by suppressing spinal dynorphin and IL-1beta expression.[7,8]
Another cutaneous cancer pain model has been established by injecting B16-BL6 melanoma cells into the plantar region of one hind paw of C57BL/6 mice. A single EA treatment showed significant analgesia on day 8 but not on day 20. EA treatments once every other day starting on day 8 showed analgesia at day 20, but EA starting on day 16 did not. The results indicate that EA exerts antihyperalgesic effects on early stage but not on late stage cutaneous cancer pain. These animal studies support the clinical use of EA in the treatment of cancer pain.
The findings of these studies suggest that acupuncture may be effective in treating cancer-related symptoms and cancer treatment–related disorders and that acupuncture may be able to activate immune functions [1,2,3] and regulate the autonomic nervous system.[4,5] Only one study reported a decrease in tumor volume in animals treated with acupuncture compared with control animals; however, the scientific value of this report is limited because of insufficient information about the research methodology.
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- Liu LJ, Guo CJ, Jiao XM: [Effect of acupuncture on immunologic function and histopathology of transplanted mammary cancer in mice] Zhongguo Zhong Xi Yi Jie He Za Zhi 15 (10): 615-7, 1995.
- Sato T, Yu Y, Guo SY, et al.: Acupuncture stimulation enhances splenic natural killer cell cytotoxicity in rats. Jpn J Physiol 46 (2): 131-6, 1996.
- Lao L, Zhang G, Wong RH, et al.: The effect of electroacupuncture as an adjunct on cyclophosphamide-induced emesis in ferrets. Pharmacol Biochem Behav 74 (3): 691-9, 2003.
- Stener-Victorin E, Lundeberg T, Waldenström U, et al.: Effects of electro-acupuncture on nerve growth factor and ovarian morphology in rats with experimentally induced polycystic ovaries. Biol Reprod 63 (5): 1497-503, 2000.
- Zhang RX, Liu B, Wang L, et al.: Spinal glial activation in a new rat model of bone cancer pain produced by prostate cancer cell inoculation of the tibia. Pain 118 (1-2): 125-36, 2005.
- Zhang RX, Li A, Liu B, et al.: Electroacupuncture attenuates bone cancer pain and inhibits spinal interleukin-1 beta expression in a rat model. Anesth Analg 105 (5): 1482-8, table of contents, 2007.
- Zhang RX, Li A, Liu B, et al.: Electroacupuncture attenuates bone-cancer-induced hyperalgesia and inhibits spinal preprodynorphin expression in a rat model. Eur J Pain 12 (7): 870-8, 2008.
- Mao-Ying QL, Cui KM, Liu Q, et al.: Stage-dependent analgesia of electro-acupuncture in a mouse model of cutaneous cancer pain. Eur J Pain 10 (8): 689-94, 2006.