甲状旁腺素相关肽核定位序列和C-末端缺失对小鼠下颌骨发育的影响

Influence of Nuclear Localization Sequence and C-Terminal Deletion of Parathyroid Hormone Relative Peptide on Mandible Development in Mice

目的:研究甲状旁腺素相关肽(parathyroid hormone relative peptide,PTHrP)核定位序列和C-末端缺失对小鼠下颌骨发育的影响。方法:使用CT扫描三维重建、HE染色、总胶原染色、碱性磷酸酶(alkaline phosphatase,ALP)染色、抗酒石酸酸性磷酸酶(tartrate resistant acid phosphatase,TRAP)染色、免疫组织化学染色和western-blot等方法对PTHrP敲入(PTHrP knock in,PTHrP KI)小鼠(PTHrP KI组,n=10)和野生型(wild type,WT)小鼠的下颌第一磨牙的差异。结果:WT小鼠成骨细胞密度、下颌骨相对骨量、ALP阳性面积、一型胶原(collagen-I)阳性面积均明显高于PTHrP KI小鼠,并且差异均具有统计学意义(P<0.05);而PTHrP KI小鼠下颌骨p16,p21和p27蛋白表达水平明显高于WT小鼠,Ki-67蛋白表达水平低于WT小鼠,并且差异均具有统计学意义(P<0.05)。结论:PTHrP核定位序列和C-末端缺失导致了成骨细胞减少,抑制了胞外基质的合成和矿化,从而导致了小鼠下颌骨的发育障碍。

Objective： To study the influence of nuclear localization sequence （NLS） and C-terminal deletion of parathyroid hormone relative peptide （PTHrP） on the mandible development in mice. Methods： Computed tomo graphy （CT） scanning, hematein eosin （HE） staining, total collagen staining, alkaline phosphatase （ALP） stab ning, tartrate-- resistant acid phosphatase （TRAP） staining, immunohistochemical staining, and western-- blot were used to compare the developmental difference of the first molar in mandible between PTHrP knock mice （PTHrP KI group, n= 10） and wild type mice （WT group）. Results： Osteoblast density, mandible relative bone mass, ALP positive area, and collagen-I positive area of WT group were markedly higher than PTHrP KI group （P〈0.05）. However, expressions of mandible p16, p21, and p27 proteins of PTHrP KI group were higher than that of the WT group, while Ki-67 protein was lower than that of the WT group, and the differences were statisti- cal significant （P〈0.05）. Conclusion： NLS and C--terminal deletion of PTHrP induce the decrease of osteoblasts and inhibit the synthesis and mineralization of extracellular matrix, thus leading to the mandible development disor- der in mice.