ABSTRACT
AIM:To investigate the effect of Bushen formulae(BHF)on bone metabolism and its possible mechanism in ovariectomized rats with high salt intake.METHODS:According to the random number table method,80 SPF-grade Sprague-Dawley rats were divided into sham group,ovariectomy(OVX)group,medium-high-salt diet(MSD)group,high-salt diet(HSD)group,BHF group,BHF with normal saline(BHF+NS)group,BHF+MSD group,and BHF+ HSD group,with 10 rats in each group.After modeling,different diets and BHF formula interventions were administered,and the concentrations of sodium chloride added to MSD group and HSD group were 2%(w/w)and 8%(w/w),respective-ly.The dose of BHF was 7.8 g·kg-1·d-1,once a day,and the treatment lasted for 12 weeks.Bone density,bone microar-chitecture,bone parameters,bone metabolism biomarkers,bone histopathological changes,the expression of epithelial sodium channel α(ENaCα),Na-Cl cotransporter(NCC),and voltage-gated chloride channel 3(ClC-3)proteins in bone tissue were detected in each group.RESULTS:Compared with sham group,the rats in OVX group had reduced bone density and destroyed bone microstructure.Compared with OVX group,the bone microstructure in MSD and HSD groups was more significantly damaged,while the levels of bone formation markers,bone glycoprotein(BGP)and type Ⅰ procolla-gen N-terminal peptide(PINP),were significantly increased in HSD group(P<0.05).Moreover,the levels of bone re-sorption markers,such as amino-terminal cross-linked telopeptides of type Ⅰ collagen(NTX),carboxy-terminal cross-linked telopeptides of type Ⅰ collagen(CTX)and tartrate-resistant acid phosphatase(TRACP),were significantly in-creased(P<0.05),indicating that bone metabolism was in high-conversion state.High-salt diet accelerated the structural destruction of bone trabeculae,and Western blot results showed that high-salt diet caused decreases in the protein expres-sion levels of ENaCα and ClC-3 and an increase in the protein expression level of NCC in femoral tissues(P<0.05).After BHF intervention,the expression of relevant ion channels caused by high salt could be regulated to different degrees.CONCLUSION:Bushen formulae could differentially regulate the expression of relevant ion channels ENaCα,ClC-3,and NCC induced by high salt to different degrees,which has certain ameliorative and therapeutic effects on the imbalance of bone metabolism.