小分子肽对成骨前体细胞MC3T3-E1骨保护素和核转录因子κB受体活化因子配体表达的影响

背景：体内实验显示,小分子肽能明显增加去卵巢大鼠的骨钙含量,使其骨密度增加,能很好地预防骨质疏松。同时体外实验显示,小分子肽能促进小鼠成骨细胞和成骨前体细胞MC3T3-E1增殖、分化、矿化,并且可能是通过抑制核转录因子p50和p65的表达来起作用。而小分子肽对骨保护素/核转录因子κB受体活化因子配体的影响尚不明确。目的：观察小分子肽对MC3T3-E1在增殖、分化、矿化过程中骨保护素和RANKL表达的影响。方法：以体积分数10%胎牛血清的DMEM培养液为空白对照组,50,100mg/L质量浓度小分子肽作用小鼠成骨前体细胞MC3T3-E1,分别于作用3,6,12,18,24,30d后,收集细胞提取蛋白,Western Blot检测骨保护素和核转录因子κB受体活化因子配体蛋白的表达。结果与结论：50,100mg/L小分子肽作用MC3T3-E1后能明显促进作用骨保护素的表达（P〈0.01）,而对核转录因子κB受体活化因子配体无明显影响。小分子肽作用后MC3T3-E1中骨保护素/核转录因子κB受体活化因子配体的比值要明显高于空白对照组（P〈0.01）。因此,认为小分子肽可以通过增加骨保护素的表达来影响骨保护素/核转录因子κB受体活化因子配体系统,间接地抑制破骨细胞的数量和功能。

Effect of the small molecular weight peptide on expression of osteoprotegerin and receptor activator of nuclear factor-kappa B ligand in MC3T3-E1 cells

BACKGROUND：The in vivo experiment indicated that the small molecular weight peptide（KP） can treat osteoporosis in ovariectomized rat by increasing the level of calcium（Ca） and bone mineral density.The in vitro experiment indicated that KP can induce the proliferation,differentiation and mineralization of MC3T3-E1 cells by inhibiting nuclear factor-κ B p50 and p65.It is unknown whether KP affects the expression of osteoprotegerin（OPG） and receptor activator of nuclear factor-κB ligand（RANKL） in osteoblasts.OBJECTIVE：To investigate the effect of KP on the expression of OPG and RANKL in MC3T3-E1.METHODS：MC3T3-E1 were cultured with various concentrations of KP（0,50 and 100 mg/L）.Osteoblasts cultured without KP were assigned as control.Collected cells and analyzed the expression of OPG and RANKL with Western Blot after treating for 3,6,12,18,24,and 30 days.RESULTS AND CONCLUSION：After 50 mg/L and 100 mg/L KP treatment,the OPG expressions in MC3T3-E1 cells were gradually increased（P 0.01）,and KP had no effect on the expression of RANKL.Compared with control,KP obviously increased the OPG/RANKL ratio（P 0.01）.Therefore,we think that KP affects the system of OPG/RANKL and indirectly inhibits osteoclast number and functions by increasing the expression of OPG,but RANKL.