Abstract

The purpose of this study was to evaluate the effect of preventive acupuncture combined with CMNS6-1 electroacupuncture on 7,12-dimethylbenzanthracene induced mammary tumors in Sprague-Dawley rats and to explore the effect of preventive acupuncture on mammary tumors from the perspective of apoptosis. 48 w old female Sprague-Dawley rats were randomly divided into control (10), model (10), tamoxifen (10) and preventive acupuncture (10) groups. The model group, tamoxifen group and preventive acupuncture group were administered once intragastrically with 100 mg/kg body weight of 7,12-dimethylbenzanthracene to induce spontaneous breast cancer. On d 1 after modeling, acupuncture plus electrical stimulation was administered to the preventive acupuncture group. Density wave was selected for electrical stimulation with a frequency of 2 Hz/100 Hz and an intensity of 1 mA and three acupoints, "Zu San Li", "San Yin Jiao" and "Tan Zhong", were stimulated for 20 min per treatment, once every other day, three times a week for 16 w. Tamoxifen (3 mg/kg body weight, intragastrically, every day) was started the day after 7,12-dimethylbenzanthracene administration and continued for 16 w, as positive control treatment. Apoptosis of breast tumor tissue cells was detected by terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, and expression of caspase-3 and B-cell lymphoma-2 was assessed by immunohistochemistry. During the experiment, no tumors were detected in rats from the control+sham group, all the rats in the 7,12-dimethylbenzanthracene+sham group developed tumors and the cumulative incidence of tumors was 100 %, meanwhile the cumulative incidence of tumors in the 7,12-dimethylbenzanthracene+preventive acupuncture group and the 7,12-dimethylbenzanthracene+tamox group were 60 % and 50 %, respectively. Terminal deoxynucleotidyl transferase dUTP nick-end labeling assay showed that preventive acupuncture could significantly promote apoptosis in breast tumor cells in 7,12-dimethylbenzanthracene induced rat, while increased the expression levels of pro-apoptotic proteins such as caspase-3 and B-cell lymphoma-2 associated X. The expression level of antiapoptotic protein B-cell lymphoma-2 was down-regulated and the ratio of B-cell lymphoma-2/B-cell lymphoma-2 associated X was increased. Preventive acupuncture therapy combined with CMNS6-1 electroacupuncture instrument inhibited 7,12-dimethylbenzanthracene-induced mammary tumorigenesis in rats and the mechanism may be related to the regulation of apoptosis-related protein expression and promotion of tumor cell apoptosis.