Effects of electroacupuncture in a mouse model of experimentally-induced osteosarcoma.

Abstract

Osteosarcoma (OSA) is a devastating form of musculoskeletal cancer that most commonly results in death due to pulmonary metastatic disease. The anti-inflammatory, immune-boosting, and analgesic effects of electroacupuncture (EA) are well-documented in a variety of animal models. To date, there are no studies investigating the gender effects of EA on OSA pain and tumor growth. We studied the effects of EA in a mouse model of experimentally-induced OSA. Electroacupuncture (4 Hz) was applied to the Zusanli (ST-36) acupuncture point at different time intervals. Each group was accompanied by a sham treatment group (no current). Primary hyperalgesia was evaluated using von Frey filaments and by quantification of spinal cfos expression. Tumor size was measured using calipers. Vaginal swabs were carried out in female mice to determine the stage of the estrous cycle during treatments. Estrous cycles in females varied greatly and were not synchronized within groups. They showed no correlation to EA or behavioral testing, indicating no direct hormonal influence. Hyperalgesia consistently increased with tumor growth, although less so in mice receiving early EA treatments. Hyperalgesia dropped slightly in all mice on the days EA was performed, but rose again 24 hours later. Tumors tended to grow slightly larger in males and resulted in higher von Frey scores and cfos expression across the groups. With few exceptions, however, there were no significant gender differences in tumor growth or von Frey scores. We conclude that early EA treatment has inhibitory effects on nociception and tumor growth that are not influenced by gender.