[Effect of electroacupuncture on plasma estrin and bone mineral density in ovariectomized rats]

To observe the effect of electroacupuncture (EA) on plasma estrin (E) 2 and bone mineral density (BMD) in ovariectomized (OVX) rats for studying its underlying mechanism in treating osteoporosis.

Thirty-two female SD rats were randomized into normal control, model, EA, and medication groups with 8 rats in each group. Postmenopausal osteoporosis model was established by removing the uterus under anesthesia (2% Phenobarbital, 40 mg/kg). In EA group, bilateral "Zusanli" (ST 32) and "Sanyinjiao" (SP 6) were punctured and stimulated electrically for 20 minutes with 1-3 Hz in frequency, 1 ms in duration of waves, and 0.7-1.0 mA in strength, once daily and 8 weeks altogether. Rats of medication group were drenched with 5% Nilestriol, 5 mL/week and for 8 weeks. At the end of experiments, blood samples were collected after removing the rat eyeball, and the left femoral bone tissue was taken. Serum E2 was assayed by using enzyme linked immunosorbent assay (ELISA) and BMD was measured by using double functional X-ray digital bone density meter.

Compared with normal group, the body weight of model group was significantly bigger (P < 0.05), and that of model group was also significantly bigger than that of EA and medication groups (P < 0.11). No significant differences were found among the 4 groups before experiments and among normal control and EA groups after treatment (P > 0.05). In comparison with normal group, BMD and serum E2 of model group decreased significantly (P < 0. 01), while compared with model group, BMD and E2 of EA and medication groups increased significantly (P < 0.01, < 0.05). No significant differences were found among normal, EA and medication groups (P > 0.05).

Both EA and medication can increase BMD and serum E2 in OVX rats, which may be one of the mechanisms of acupuncture in treating osteoporosis.