Objective To explore the effect of iron on bone formation with or without estradiol.Methods 8-week old female ICR mice 25±1 g were randomly divided into 3 groups (n=7 each):SHAM group,OVX group and F+OVX group,which were intervened by ferric ammonium citrate (FAC) with a dose of 0.10 g/kg per week.After 8 weeks,the mice of OVX group and F+ OVX group were spayed (with ovariotomy).12 weeks later,body weight,serum ferritin were measured.The expression changes of Runx2,Osterix,Bglap,OPG,ER-α,ER-β derived from mice tibiae were detected by RT-PCR.A high resolution Micro-CT was used to scan the femur.Primary osteoblasts,extracted from suckling mice' s cranium,were intervened by FAC and estradiol.Har-vested cells after 24 h,then operated alkaline phosphatase staining and q-PCR.Gene expressions of Runx2,osterix and Bglap were measured.Results There were no significant difference between every group in body weight The serum Fer was heightened in F+OVX group (324.82±38.60 μg/L) comparing with SHAM group (39.40±3.81 μg/L) and OVX group (41.38±5.56 μg/L).The differences were statistically significant among the three groups.BMD of O VX group (0.114±0.013 mg/mm3) was lower than that of SHAM group (0.297±0.072 mg/mm3),but higher than that of F+OVX group (0.902±0.064 mg/mm3),The differences were statistically significant among the three groups.RT-PCR results:The expressions of OPG,Runx2,osterix,Bglap and ER-β were decreased after ovariotomy,while the level of osterix and OPG dropped further with the treatment of FAC.In vitro experiment,results of ALP staining suggested that FAC decrease the level of ALP.Q-PCR showed that the expressions of Runx2,osterix were reduced by FAC,while estradiol increased Bglap expression.Conclusion Iron accumulation might have further result in inhibition of bone formation and suppression of osteogenic activity without estradiol.%目的 探讨单纯雌激素下降和雌激素下降+铁蓄积两种状况下,小鼠骨组织骨量、成骨活性指标、原代成骨细胞代谢指标的差异.方法 第一部分:将体重(25±1)g的ICR小鼠按体重区组随机化分组分为3组,每组7只:(1)去势组,模拟绝经状态;(2)高铁去势组,模拟绝经状态合并铁蓄积,该组小鼠采用“去势”后行枸橼酸铁铵腹腔注射;(3)假手术组.12周后检测指标:小鼠体重、血清铁蛋白;胫骨组织的成骨特异性转录因子(Runx2、Osterix)、骨钙蛋白(Bglap)、骨保护素、雌激素受体α、β(ER-α、ER-β)基因表达;Micro-CT分析股骨远端骨量差异.第二部分:提取新生ICR小鼠颅骨原代成骨细胞,用枸橼酸铁胺、17β-雌二醇(E2)腹腔注射干预,碱性磷酸酶染色观察成骨细胞形态,定量PCR(q-PCR)检测成骨相关基因表达.结果 各组小鼠体重无统计学差异;血清铁蛋白含量:高铁去势组[(324.82±38.60) μg/L]较去势组[(41.38±5.56)μg/L]及假手术组[(39.40±3.81) μg/L]升高,差异有统计学意义(2) Micro-CT的骨密度:高铁去势组[(0.902±0.064) mg/mm3]及去势组[(0.114±0.013)mg/mm3]较假手术组[(0.297±0.072) mg/mm3]均下降,差异有统计学意义,高铁去势组比去势组下降更显著.(3)RT-PCR:与假手术组相比,去势组骨保护素、Runx2、Osterix、Bglap、ER-β表达降低;高铁去势组Osterix、骨保护素表达更低.(4)成骨细胞碱性磷酸酶染色显示用枸橼酸铁胺干预后细胞变小,棕色变淡;q-PCR结果显示:E2升高Bglap表达,枸橼酸铁胺下调Runx2,Osterix表达水平.结论 当雌激素去除时,如合并铁增加,则成骨活性指标进一步下调、骨形成进一步受到抑制.
展开▼
