Root development in mice lacking functional tissue non-specific alkaline phosphatase gene: Inhibition of acellular cementum formation
Root development in mice lacking functional tissue non-specific alkaline phosphatase gene: Inhibition of acellular cementum formation
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DOI：
10.1177/00220345990780060501
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发表时间：
1999-06-01
影响因子：
7.6
通讯作者：
Everts, V
中科院分区：
文献类型：
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作者：
Beertsen, W;VandenBos, T;Everts, V
组织非特异性碱性磷酸酶(TNAP)广泛存在于发育中的牙齿中，包括牙周膜细胞。在这里，我们研究了缺乏TNAP基因的小鼠的牙齿和牙根发育。杂合子突变体来自杰克逊实验室，动物资源(巴尔港，美国，ME)并培育。TnAP基因缺陷小鼠及其仔鼠在出生后6~25天处死，取磨牙块进行光镜和电子显微镜观察。观察到切牙向口腔的萌出延迟2~3天。此外，磨牙根部的外套质牙本质矿化的开始时间也推迟了2-3天。然而，在纯合子突变体中，牙本质和釉质的形成显示出或多或少的正常模式，除了局限性的釉质减少。最明显的发现是沿磨牙根无细胞牙骨质的缺陷形成。牙骨质不是连续的一层，而是以非常薄且不规则形状的斑块形式沉积在牙周韧带纤维的底部。Sharpey的纤维较短且发育不良。相比之下，牙槽骨、牙周膜和细胞牙骨质的发育似乎没有受到影响。结论：TnAP在地幔牙本质矿化和脱细胞牙骨质形成过程中起着重要作用。
Tissue non-specific alkaline phosphatase (TNAP) is richly present in developing teeth including the cells of the periodontal ligament. Here, we investigated tooth and root development in mice lacking the TNAP gene. Heterozygous mutants were obtained from The Jackson Laboratory, Animal Resources (Bar Harbor, ME, USA) and bred. TNAP-deficient mice and their littermates were killed from 6 to 25 days after birth and their molar blocks processed for light and electron microscopy. It was observed that the eruption of the incisors into the oral cavity was delayed for 2 to 3 days. Also, the onset of mineralization of the mantle dentin in the roots of the developing molars was delayed for 2 to 3 days. Yet, dentin and enamel formation in the homozygous mutants showed a more or less normal pattern, with the exception of localized enamel hypoplasias. The most conspicuous finding was the defective formation of acellular cementum along the molar roots. Instead of a continuous layer, the cementum was deposited as very thin and irregularly shaped patches around the bases of the periodontal ligament fibers. Sharpey's fibers were short and poorly developed. In contrast, the development of the alveolar bone, the periodontal ligament, and the cellular cementum was seemingly unaffected. It is concluded that TNAP represents an essential factor in mantle dentin mineralization and in the formation of acellular cementum.