Objective To observe the effect of electroacupuncture(EA) on expression of histone deacetylase 2(HDAC2)

histone H3

bone formation related genes and proteins in osteoporosis rats

so as to reveal its mechanisms underlying improvement of osteoporosis. Methods Female SD rats were randomly divided into 4 groups:sham operation

model

EA and medication(n= 10 rats in each group). The osteoporosis model was established by castration. EA(2 Hz

1 mA) was applied to bilateral "Shenshu"(BL23) and "Pishu"(BL20) for 10 min

once every other day for 8 weeks. Rats of the medication group received subcutaneous injection of 17 β-estradiol(100 μg/kg

20 μg/mL). The bone quality and quantity including the cortical bone mineral density(CBMD)

trabecular bone mineral density(TBMD)

ratio of bone volume/total volume(BV/TV)

trabecular thickness(Tb.Th)

trabecular number(Tb.N)

trabecular separation(Tb. Sp)

trabecular bone pattern factor(Tb.Pf)

and structure model index(SMI) of the right thigh-bone were detected by using a micro-computed tomography. Serum alkaline phosphatase(ALP) and estrogen 2(E2) contents were assayed by using colorimetry and ELISA

expression levels of HDAC2

histone H3 and Runx2 in the thigh-bone were detected using Western blot

and that of Runx2 mRNA was detected using quantitative real-time PCR

separately. The co-expression of Ac-histone H3/Runx2 and Runx2/ALP was observed by using immunofluorescence histochemical staining.Methods After modeling

the levels of TBMD

BV/TV

Tb.Th

and Tb.N

serum E2 and ALP

and expression of Runx2 protein and mRNA

Ac-histone and ALP proteins were significantly lower(P<0.01)

and those of Tb.Sp

Tb.Pf and SMI

HDAC2 and histone H3 proteins were significantly higher(P<0.01) in the model group than those in the sham operation group. After the interventions

the decrease of TBMD

BV/TV

Tb.N

Runx2 protein and mRNA

ALP in both EA and medication groups

serum E2 in the medication group

and Ac-histone H3 in the EA group

and the increase of Tb.Sp in the medication group

Tb.Pf

SMI

and HDAC2 in both EA and medication groups

and histone H3 in the EA group were reversed(P<0.01

P<0.05). No significant changes were found in the levels of CBMD after modeling relevant to the sham operation group

and after EA and medication interventions(P>0.05). The effects of EA were significantly superior to 17 β-estradiol in down-regulating the expression of HDAC2 and histone H3 proteins and in up-regulating expression of Ac-histone H3 protein(P<0.01

P<0.05).Conclusion EA treatment can increase bone density

increase bone mass and trabecular bone

and promote trabecular bone rod-like changes in plate shape in osteoporosis rats

which is related to its effect in up-regulating the expression of Ac-histone H3 protein

and down-regulating the expression of bone formation-related proteins.