Objective To observe the effect of electroacupuncture(EA)stimulation of"Mingmen"(GV 4)on the bone morphogenetic protein-2(BMP-2)content and biomechanics in osteoporosis rats so as to explore its mechanism underlying improvement of osteoporosis.Methods Fifty female SD rats were randomized into sham operation(sham)

model

EA-GV 4

EA-non-acupoint(non-acupoint)and estrogen(medication)groups

with 10rats in each group.Postmenopausal osteoporosis model was established by removing the rats' bilateral ovaries under anesthesia.EA(2Hz/15Hz

1.0mA)was applied to"Mingmen"(GV 4)or non-acupoint for 20min

once daily for 30times

with one day's interval between every two 10times.Rats of the medication group were lavaged with Pentanoic Acid Estradiol(25μg/mL

2mL/500g)

once every day(the dosage of estradiol was adjusted according to their body weight)continuously for 1month.Rats of the model and sham groups experienced the fixing and fastening procedures as the other rats in the EA and medication groups.After intervention

the BMP-2expression level of the femoral bone tissue

and bone biomechanical values were determined by immunohistochemistry and three-point bending tests

respectively.Results ①In comparison with the sham operation group

the femoral biochemical maximum load and fracture load values were significantly decreased in the model group(P<0.05).While compared with the model group

the biochemical maximum load and fracture load values were obviously increased in the EA-GV 4and medication groups(P<0.05)

but not in the non-acupoint group(P>0.05).② Compared with the sham group

the femoral BMP-2expression of model group was significantly decreased(P<0.05)

compared with the model group

the expression of BMP-2of GV 4and medication groups significantly increased(P<0.05).Conclusion EA-GV 4intervention can improve bone biomechanical changes in osteoporosis rats.