Effect of iron saturation level of lactoferrin on osteogenic activity in vitro and in vivo.
Effect of iron saturation level of lactoferrin on osteogenic activity in vitro and in vivo.
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DOI：
10.3168/jds.2012-5692
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发表时间：
2013
影响因子：
3.5
通讯作者：
X. Y. Wang;H. Guo;W. Zhang;P. Wen;H. Zhang;Z. Guo;F. Ren
中科院分区：
文献类型：
--
作者：
X. Y. Wang;H. Guo;W. Zhang;P. Wen;H. Zhang;Z. Guo;F. Ren
我们研究了铁饱和度对乳铁蛋白(LF)体外和体内成骨活性的影响。制备了不同铁饱和度的LF1.0、9.0、38、58和96%的样品：Apo-Lf、Lf-9、Lf-38、Lf-58和Holo-Lf。采用四甲基偶氮唑盐(3-(4，5-dimethylthiazol-2-yl)-2，5-diphenyltetrazolium)比色法观察到，在100和1000μg/mL铁饱和度下，LF刺激成骨细胞增殖的活性随铁饱和度的增加而降低。将4周龄ICR雄性小鼠随机分为4组：空白对照组(生理盐水)、阴性对照组(BSA)、载脂蛋白-乳铁蛋白(apo-LF)和全脂蛋白-乳铁蛋白(holo-LF)。4组小鼠在头盖骨表面皮下注射生理盐水、BSA、apo-Lf或Holo-Lf，每天2次，连续5天，剂量为4 mg/kg/d。骨组织形态计量学显示，apo-LF组的新骨形成(用四环素-盐酸标记进行评估)倾向于比holo-LF组更强。利用荧光光谱和圆二色谱测量发现，随着铁饱和程度的增加，色氨酸的曝光量增加，α-螺旋含量增加，而β-结构含量减少。这些结果表明，在体内外，随着铁饱和度的增加，LF的成骨活性降低，这可能与LF的构象变化有关。
We studied the effect of iron saturation level on the osteogenic activity of lactoferrin (LF) in vitro and in vivo. Different iron saturation levels of LF (1.0, 9.0, 38, 58, and 96%) were prepared as the following samples: apo-LF, LF-9, LF-38, LF-58, and holo-LF. Using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, we observed that the stimulating osteoblast proliferation activity of LF in vitro decreased with increasing iron saturation level at 100 and 1,000 μg/mL. In vivo, 4-wk-old ICR Swiss male mice were randomly divided into 4 groups: blank control (physiological saline), negative control (BSA), apo-LF, and holo-LF. Four groups of mice were injected subcutaneously with physiological saline, BSA, apo-LF, or holo-LF over the calvarial surface twice a day for 5 consecutive days at a dose of 4 mg/kg per day. Bone histomorphometry showed that new bone formation (assessed using tetracycline-HCl labels) tended to be stronger with apo-LF than with holo-LF. Using fluorescence spectroscopy and circular dichroism measurements, we found that exposure of tryptophan increased, α-helix content increased, but β-structure content decreased with increasing iron saturation level. These findings indicated that the osteogenic activity of LF decreases with increasing iron saturation level in vitro and in vivo, which may be related to conformational changes in LF.