Objective To observe the effect of electroacupuncture of"Guanyuan"(CV 4)on bone miner density

bone biomechanics

serum osteocalcin(BGP)and alkaline phosphatase(ALP)contents

and femoral osteoblastic Wnt-β-catenin signaling in postmenopausal osteoporosis(PMOP)rats.Methods Forty female SD rats were randomly divided into sham operation(sham)

model

EA-CV 4

and EA-non-acupoint(below the costal region)groups(n=10in each group).The PMOP model was established by performing an ovariectomy in the rats of the later 3groups.EA(2Hz

1mA)was applied to CV 4for 20 min

once daily for one month

with one day's break between every 10 days.After the treatment

serum BGP and ALP contents were detected using ELISA

the right femoral bone miner density and biomechanics(maximum load

breakage load)were measured using a Dual Energy X-Ray Bone Densitometer and a Universal Material Testing Instrument

respectively.The expression levels of Wnt 3a mRNA

β-catenin mRNA and the bone-specific factors runt-related transcription factor 2(Runx 2)mRNA of the femoral bone tissue were determined by real time RT-PCR.Results HE staining results suggested EA of"Guanyuan"(CV 4)can improve the morphological changes(trabeculae)of osteoporosis in ovariectomized rats.Compared with the control group

femoral maximum load and breakage load

bone density and serum BGP and ALP contents

femoral Wnt 3amRNA

β-catenin and Runx 2mRNA expression levels

and femoral Wnt 3aandβ-catenin immunoactivity were significantly down-regulated in the ovariectomized rats(model group)(P<0.05).Following EA treatment

all the decreased levels of femoral maximum load and breakage load

bone density and serum BGP and ALP

femoral Wnt 3amRNA and protein

β-catenin mRNA and protein and Runx 2mRNA expression were obviously reversed in the EA-CV 4group(P<0.05)rather than in the non-acupoint group(P>0.05).Conclusion EA of CV 4can improve the femoral biomechanics

increase bone density in OVX rats

which are associated to its effects in up-regulating levels of serum BGP and ALP

femoral Wnt 3amRNA and protein

β-catenin mRNA and protein and Runx 2mRNA expression

suggesting an involment of improved bone metabolism and activation of osteoblastic Wnt-β-catenin signaling.