Objective To observe the effect of electroacupuncture(EA) on uterine microcirculation in dysmenorrhea rats so as to investigate its mechanism underlying relieving primary dysmenorrheal(PD).Methods Female SD rats undergoing diestrus were randomly divided into saline control

model

Sanyinjiao(SP 6)

Xuanzhong(GB 39) and non-acupoint groups

with 6 rats in each.PD model was established by subcutaneous injection of estradiol benzoate for 10 days and intra-peritoneal injection of oxytocin(2 U) 1 h after the last estradiol injection.EA(2 Hz/100 Hz

1-1.5 mA) was applied to the above-mentioned acupoints and non-acupoint area for 20 minutes.Numbers and diameters of the uterine microvessels(11-100 μm) and capillaries(≤10 μm)

and the state of the uterine microcirculation were observed by using a Cold Light Microcirculation Detector.ResultsIn comparison with the saline control group

the numbers and diameters of uterine microvessels and capillaries at the correspon-ding time-points 5 min

10 min and 20 min were decreased significantly in the model group(P<0.05

P<0.01).While compared with the model group

the numbers and diameters of uterine microvessels and capillaries at 20 min after EA in the SP 6 group were increased significantly(P<0.05).The diameter of uterus capillaries of SP 6 group was significantly bigger than that of the non-acupoint group at the time-point 20 min(P<0.05).No significant differences were found among the SP 6

GB 39 and non-acupoint groups in the diameter of uterine microvessels(P>0.05).Conclusion EA of SP 6 can effectively increase the number of ute-rine microvessels and capillaries and the diameter of the uterine microvessels and capillaries in PD rats

which may contribute to its effect in relieving dysmenorrhea by improving uterine microcirculation.