Eruptive and functional changes in periodontal ligament fibroblast orientation in CD44 wild-type vs. knockout mice.
Eruptive and functional changes in periodontal ligament fibroblast orientation in CD44 wild-type vs. knockout mice.
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DOI：
10.1111/jre.12113
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发表时间：
2014-06
影响因子：
3.5
通讯作者：
Hinderberger H
中科院分区：
文献类型：
--
作者：
Popowics T;Boyd T;Hinderberger H
牙周韧带（PDL）成纤维细胞在牙齿萌出期间形成韧带的主要纤维，并在咬合过程中维持这些纤维。牙周韧带的发育和咬合适应包括牙周韧带成纤维细胞方向的改变，然而，这些方向改变的机制尚不清楚。本研究的目的是比较CD44野生型（WT）和敲除型（KO）小鼠在第一磨牙萌出和咬合不同阶段的牙周韧带成纤维细胞方向。
将CD44 WT和KO小鼠饲养至与第一磨牙（M1）萌出（出生后8、11、14、18天，dpn）和咬合（出生后26和41天，dpn）相对应的6个出生后阶段。制备下颌第一磨牙（M1）的冠状切片，并测量牙颈部牙根区域成纤维细胞的方向。使用沃森 - 威廉姆斯F检验（Oriana软件）和协方差分析（ANCOVA）对不同发育阶段以及不同品系之间的角度测量值进行比较。
在骨内萌出（第11天）、黏膜穿透（第14天）和咬合前萌出（第18天）之间，CD44 WT（9 - 87°）和KO小鼠（14 - 93°；p≤0.05）的牙周韧带成纤维细胞方向显著增加，然而，随着咬合开始（第26天）或持续功能（第41天），牙周韧带成纤维细胞方向没有显著变化。在每个品系内，咬合前萌出（第18天）时成纤维细胞方向的方差显著高于所有其他时间点的方差（p < 0.0005）。CD44 WT和KO小鼠显示出相似的牙周韧带发育和萌出模式，仅在早期功能阶段（第26天，92°对116°；p = 0.05）CD44 WT和KO成纤维细胞方向存在显著差异。
CD44 WT和KO小鼠之间牙周韧带成纤维细胞方向的发育高度相似。在早期（第11天）和晚期（第18天）萌出阶段之间，牙周韧带成纤维细胞方向增加，与M1的向上移动相对应。在咬合前萌出（第18天）时形成的牙周韧带成纤维细胞方向在咬合功能的早期（第26天）和晚期（第41天）阶段得以维持，这表明牙周韧带细胞在M1咬合之前就适应了口腔中的机械负荷。
Periodontal ligament (PDL) fibroblasts establish the principal fibers of the ligament during tooth eruption, and maintain these fibers during occlusion. PDL development and occlusal adaptation includes changes in the orientation of PDL fibroblasts, however, the mechanism for these changes in orientation is unclear. The objective of this study was to compare the periodontal ligament fibroblast orientation in different stages corresponding with first molar eruption and occlusion in CD44 wild-type (WT) and knockout (KO) mice. CD44 WT and KO mice were raised to 6 postnatal stages corresponding with first molar (M1) eruption (8, 11, 14, 18 days dpn) and occlusion (26 and 41 days dpn). Coronal sections of the first mandibular molar (M1) were prepared and the orientation of fibroblasts in the cervical root region was measured. Angle measurements were compared across developmental stages and between strains using Watson-Williams F-test (Oriana software) and ANCOVA. PDL fibroblast orientation increased significantly in CD44 WT (9–87°) and KO mice (14–93°; p ≤ 0.05) between intraosseous eruption (Day 11), mucosal penetration (Day 14), and preocclusal eruption (Day 18), however, the PDL fibroblast orientation did not change significantly with the onset of occlusion (Day 26) or continued function (Day 41). Within each strain, the variance in fibroblast orientation during preocclusal eruption (Day 18) was significantly higher than the variance of all other timepoints (p < 0.0005). CD44 WT and KO mice showed a similar pattern of PDL development and eruption with a significant difference in CD44 WT vs. KO fibroblast orientations only during early function (Day 26, 92° vs 116°; p = 0.05). The development of PDL fibroblast orientation is highly similar between CD44 WT and KO mice. Between early (Day 11) and late (Day 18) eruptive stages PDL fibroblast orientation increases, corresponding with the upward movement of M1. The PDL fibroblast orientation established in preocclusal eruption (Day 18) is maintained during early (Day 26) and late (Day 41) stages of occlusal function, suggesting that PDL cells adapt to mechanical loads in the oral cavity prior to M1 occlusion.