[Influence of electroacupuncture stimulation of delivery-facilitating acupoints with different stimulating parameters on serum endocrine hormones of late-stage pregnant rats].

OBJECTIVE: To observe the influence of electroacupuncture (EA) stimulation of "Hegu" (LI 4) and "Sanyinjiao"(SP 6; a classical delivery-facilitating acupoint recipe) at different parameters on endocrine hormone levels of late-stage pregnant rats, so as to find the better stimulation parameters for delivery facilitation. METHODS: Ninety-six female Wistar rats were randomly divided into eight groups: normal control (normal), pregnancy (model), EA-15 Hz, EA-30 Hz, EA-50 Hz, EA-2 Hz/ 15 Hz, EA-2 Hz/30 Hz and EA-2 Hz/50 Hz, with 12 rats in each group except EA-30 Hz group (n = 10). EA stimulation (0.2 to 0. 3 mA) was delivered to bilateral LI 4 for 20 min and then bilateral SP 6 for 5 min (25 min). The contents of serum estradiol (E2), progesterone (P) and prostaglandin E2 (PGE2) were detected by ELISA. RESULTS: Compared with the normal group, serum E2, P and PGE2 contents were significantly increased in the pregnancy model group (P<0.01), and E2/ P level was downregulated mildly (P>0.05). Compared with the model group, the contents of serum E2 in the EA-15 Hz, EA-30 Hz, EA-50 Hz, EA-2 Hz/15 Hz and EA-2 Hz/50 Hz groups, serum PGE2 contents in the EA-15 Hz, EA-30 Hz and EA-2 Hz/50 Hz groups, and E2/P levels in the EA-15 Hz, EA-30 Hz, EA-50 Hz and EA-2 Hz/50 Hz groups were significantly increased (P<0.01, P<0.05), whereas serum P contents in the EA-15 Hz, EA-30 Hz, EA-50 Hz and EA-2 Hz/50 Hz groups were significantly down-regulated (P<0. 01, P<0. 05). The effects of EA-2 Hz/50 Hz group were significantly superior to those of EA-2 Hz/15 Hz and EA-2 Hz/ 30 Hz groups in raising serum E2 and E2/P levels (P<0.05, P<0.01). No significant differences were found among the EA-15 Hz, EA-30 Hz, EA-50 Hz and EA-2 Hz/50 Hz groups in raising serum E2, PGE2 and E2/P levels, and among the EA-30 Hz, EA-50 Hz and EA-2 Hz/50 Hz groups in lowering serum P levels (P>0. 05). It displayed that the effects of EA at 15 Hz, 30 Hz and 2 Hz/50 Hz on the abovementioned 4 indexes were relatively better. CONCLUSION: EA of LI 4 and SP 6 at 15 Hz, 30 Hz and 2 Hz/ 50 Hz can effectively up-regulate serum E2, PGE2 and E2/P levels and down-regulate serum P content in pregnancy rats, which may contribute to its effect in promoting labor.