[Electroacupuncture Intervention Reduces Mammary Gland Hyperplasia by Regulating Serum Estradiol and Progesterone Levels and Their Mammary Receptor Expression in Female Rats].

Objective: To observe the effect of electroacupuncture (EA) intervention on hyperplastic mammary glands, serum estradiol (E ₂ ) and progesterone (P) contents, estrogen receptor alpha (ERα) and progesterone receptor (PR) expression of breast tissues in mammary gland hyperplasia (MGH) rats, so as to reveal its mechanisms underlying improvement of MGH.
Methods: Sixty female SD rats were randomly divided into control, model, EA, EA＋ovariectomy(OVX) and EA＋sham-OVX groups ( n ＝12 in each). The MGH model was established by injection of Estradiol Benzoate injection (0.5 mg/kg, once daily for 25 d) and P injection (0.5 mg/kg, once daily for 5 d after estradiol injection) into the medial hind-leg muscle. After model establishment, bilateral OVX was performed for rats of the EA＋OVX group, and sham OVX (only exposure of ovaries) was performed for rats of the EA＋sham OVX group. EA (2 Hz, 2 mA) was applied to bilateral "Tianzong"(SI 11), "Ganshu"(BL 18), "Zusanli" (ST 36) for point group A, and "Wuyi"(ST 15), "Hegu"(LI 4), "Danzhong" (CV 17) for point group B for 20 min, once daily, 5 days a week for 4 weeks. The two acupoint groups were used alternately. The height of the rats' nipples (the 2 ^nd pairs) were measured. Serum E ₂ and P levels were assayed by ELISA. The expression of ERα and PR in mammary tissues was detected by immunofluorescence staining and Western blot, separately.
Results: The height of nipples, serum E ₂ content, and mammary ERα protein expression level were significantly higher in the model group than in the control group ( P <0.01), while serum P content and PR expression were remarkably lower in the model group than in the control group ( P <0.01). Following EA intervention, the height of nipples, serum E ₂ content and mammary ERα protein expression level in both EA and EA＋sham OVX groups, and ERα expression in the EA＋OVX group were considerably lower in comparison with those of the model group( P <0.01), and serum P content and PR expression in the 3 EA groups were significantly higher than those in the model group ( P <0.01， P <0.05). But there were no significant changes in the nipple height and serum E ₂ levels in the EA＋OVX group relevant to the model group ( P >0.05), suggesting an important role of the ovary in producing EA's effect.
Conclusion: EA intervention can improve hyperplastic mammary glands by down-regulating serum E ₂ content and mammary ERα protein expression, and up-regulating serum P content and PR expression in MGH rats, which has a close relation with the intact ovaries.