[Electroacupuncture at intercostal nerve for mammary gland hyperplasia in rats]

To explore the correlation between efficacy of electroacupuncture (EA) on mammary gland hyperplasia (MGH) and the regulatory pathway of intercostal nerve.

Fifty female SD rats were randomly divided into a blank group (group A, 12 rats), a model group (group B, 12 rats), an EA group (group C, 13 rats) and an intercostal nerve transection group (group D, 13 rats). The rats in the group B, group C and group D were prepared into MGH model; after model was successfully prepared, the 7th intercostal nerve was cut off in the group D. EA was applied at back acupoints including bilateral "Tianzong" (SI 11), "Ganshu" (BL 18) and "Shenshu" (BL 23) as well as chest acupoints including bilateral "Wuyi" (ST 15), "Hegu" (LI 4) and "Danzhong" (CV 17) in the group C and D. The two groups of acupoints were selected alternately. EA was given for 20 min, once a day; 5-day treatment was taken as one course; there was an interval of 2 days between course; totally 20 treatments were given. After treatment, the height and diameter of papilla were observed; the contents of serum estradiol (E₂) and progestin (P), the expression of estrogen receptor α (ERα) and progestrone receptor (PR) in mammary gland were measured.

(1) The height and diameter of papilla: after treatment, the height and diameter of papilla in the group C were significantly smaller than those in the group B (both P<0.05); the height and diameter of left-side papilla in the group D were significantly bigger than those in the group C (both P<0.05). (2) Serum E₂ and P: after treatment, compared with the group B, the contents of E₂ and E₂/P were reduced and the content of P was increased in the group C and group D (all P<0.05). Compared with the group C, the contents of E₂ and E₂/P were increased and the content of P was reduced in the group D (all P<0.05). (3) ERα and PR in mammary gland: compared with the group B, the content of ERαwas decreased and the content of PR was increased in the group C (both P<0.05). Compared with the group C, the content of ERαwas increased and the content of PR was decreased in the group D ((both P<0.05).

The efficacy mechanism of EA for MGH is likely to be related with the pathway of intercostal nerve; the mechanism may be acupuncture regulating the contents of serum E₂ and P as well as contents of ERα and PR in mammary gland.