黄芩素对骨质疏松大鼠骨形成的影响及其机制OA

Objective To explore the therapeutic effect and molecular mechanism of baicalein on osteoporosis model rats.Methods The osteoporosis rat model was established by removing bilateral ovaries,and the model rats were divided into model group,low-dose baicalein group,medium-dose baicalein group and high-dose baicalein group,with 10 rats in each group.Ten rats without removing bilateral ovaries were set as sham group.After successful modeling,rats in low-dose,medium-dose and high-dose groups were given baicalein at doses of 10 mg/kg,20 mg/kg and 40 mg/kg by gavage,once a day for 12 weeks.The bone microstructure of the femur in the left hind limb of rats was analyzed by Micro-CT scanning,including bone mineral density(BMD),trabecular bone count(Tb.N),trabecular bone thickness(Tb.Th),and trabecular bone separation degree(Tb.Sp).The lesions of femoral tissues were examined by HE staining and retinol O-solid green staining,and the content levels of inflammatory factors[interleukin-6(IL-6),tumor necrosis fac-tor-α(TNF-α),interleukin-1β(IL-1β)]and bone resorption markers[C-telopeptide of typeⅠcollagen(CTX-Ⅰ)and tartrate resistant acid phosphatase 5b(TRACP-5b)]in serum were detected by ELISA.Osteoblast MC3T3-E1 was divided into control group,dexa-methasone group,baicalein 5 µmol/L group,baicalein 10 µmol/L group and baicalein 20 µmol/L group.Osteoblast proliferation was detected by the CCK-8 method,osteoblast apoptosis was detected by TUNEL staining,and osteoblast mineralized nodules were detected by Alizarin red staining.The protein expression levels of bone formation factors[osteoprotegerin(OPG),osteocalcin(BGP),receptor activator of nuclear factor κB ligand(RANKL)]and Wnt/β-catenin signaling pathway protein factors[WNT family member 3A(Wnt3a),β-catenin,glycogen synthase kinase-3 β(GSK-3β)]in osteoblasts and femoral tissue were detected by Western blot.Results The femoral tissue structure and the morphology of rats in sham group were normal.The femoral structure of rats in model group was severely damaged.The tissue structure and the morphology of the femur in rats in low-dose baicalein group,medium-dose baicalein group and high-dose baicalein group gradually returned to the normal.Compared with sham group,BMD,Tb.N and Tb.Th in model group were all decreased(P<0.05),and Tb.Sp was increased(P<0.05);the levels of IL-1β,IL-6,TNF-α,CTX-I and TRACP-5b in serum were all increased(P<0.05),while the protein levels of OPG,BGP,Wnt3a,β-catenin and GSK-3β in femoral tissue were all decreased(P<0.05),and the protein level of RANKL was increased(P<0.05).Compared with model group,BMD,Tb.N and Tb.Th in low-dose baicalein group,medium-dose baicalein group and high-dose baicalein group were all increased(P<0.05),and Tb.Sp was decreased(P<0.05);the levels of IL-1β,IL-6,TNF-α,CTX-I and TRACP-5b in serum were all decreased(P<0.05),the protein levels of OPG,BGP,Wnt3a,β-catenin and GSK-3β in femoral tissue were all increased(P<0.05),and the protein level of RANKL was decreased(P<0.05).Compared with control group,the cell proliferation activity in dexamethasone group was decreased(P<0.05),the positive rate of TUNEL was increased(P<0.05),and the formation of calcified nodules decreased;the protein levels of OPG,BGP,Wnt3a,β-catenin and GSK-3β were all decreased(P<0.05),while the protein level of RANKL was increased(P<0.05).Compared with dexamethasone group,the cell proliferation activity in baicalein 5 µmol/L group,baicalein 10 µmol/L group and baicalein 20 µmol/L group were increased(P<0.05),the positive rate of TUNEL were decreased(P<0.05),and the for-mation of calcified nodules gradually increased;the protein levels of OPG,BGP,Wnt3a,β-catenin and GSK-3β were all increased(P<0.05),while the protein level of RANKL were decreased(P<0.05).Conclusion Baicalein can improve the bone microstructure and the osteoblast activity of osteoporosis model rats by inhibiting bone resorption and inflammatory responses,promoting bone forma-tion and osteoblast function,which may be related to the activation of Wnt/β-catenin signaling pathway.