Distribution of the epithelial rests of Malassez and their relationship to blood vessels of the periodontal ligament during rat tooth development
Distribution of the epithelial rests of Malassez and their relationship to blood vessels of the periodontal ligament during rat tooth development
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DOI：
10.2478/aoj-2003-0010
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发表时间：
2003-11
影响因子：
0.4
通讯作者：
Petrina S P Kat;W. Sampson;David F. Wilson;O. Wiebkin
中科院分区：
文献类型：
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作者：
Petrina S P Kat;W. Sampson;David F. Wilson;O. Wiebkin
摘要 背景：有一些证据表明，马拉塞斯上皮细胞将牙根表面与牙周膜血管分开，并可能保护牙根免于吸收。目的：本研究的目的是确定发育中的大鼠第一磨牙萌出前、萌出期间和萌出后马拉塞斯上皮残留（ERM）和牙周膜（PDL）血管的分布。方法：4只Sprague-Dawley大鼠在两天、一周、两周、三周、四周和六周龄处死。处理后，将上颌骨包埋在石蜡中，并进行纵向和横向切片。采用双重免疫组织化学技术对切片进行染色，该技术利用角蛋白抗体 AE1–AE3 (1:2,000) 和内皮抗体因子 VIII (1:10,000) 来同时标记 ERM 和血管。从三周、四周和六周龄大鼠的近颊根部获得 ERM 和血管计数，同时对早期发育阶段进行定性观察。结果：在第三周、第四周和第六周阶段，在 PDL 宽度的三分之一的牙齿中发现了 ERM 细胞和细胞簇。细胞和细胞簇的数量随着年龄的增长而增加，特别是在近颊根的上三分之一处。在所有年龄组的根部远端表面都发现了最多数量的细胞和细胞簇。所有根表面的细胞和簇从三周增加到四周，但从四周减少到六周。在 PDL 的骨侧三分之一处发现了最多的血管。远端表面的血管比例最高，腭表面的比例最少。从三到四周龄起，所有表面象限中的血管数量变化不大，但从四周龄到六周龄时有所增加，可能是对牙齿萌出和咬合功能的反应。生理性牙根吸收仅在牙齿萌出后观察到，似乎与 ERM 网络连续性丧失和血管侵入有关。结论：正畸牙根吸收可被视为对 PDL 稳态控制丧失的过度反应，可能是由 Malassez 上皮残存介导的。
Abstract Background: There is some evidence that the epithelial cell rests of Malassez partition the root surface from the periodontal ligament blood vessels, and may protect the root from resorption. Objective: The aim of the present study was to determine the distributions of the epithelial rests of Malassez (ERM) and blood vessels in the periodontal ligament (PDL) of the developing rat first molar before, during and after emergence. Methods: Four Sprague-Dawley rats were sacrificed at two days, one week, two weeks, three weeks, four weeks and six weeks of age. After processing, the maxillae were embedded in paraffin, and sectioned longitudinally and transversely. The sections were stained with a double immuno-histochemical technique which utilised a keratin antibody AE1–AE3 (1:2,000) and an endothelial antibody Factor VIII (1:10,000) to enable simultaneous labelling of ERM and blood vessels. ERM and blood vessel counts were obtained from the mesio-buccal roots of three week, four week and six week-old rats, whilst qualitative observations were made for the earlier developmental stages. Results: ERM cells and cell clusters were found in the tooth third of the PDL width at the three, four and six week stages. Cells and cell clusters increased in number with age, especially in the upper third of the mesio-buccal root. The largest numbers of cells and clusters were found on the distal surfaces of the roots in all age groups. Cells and clusters in all root surfaces increased from three to four weeks, but decreased from four to six weeks. The greatest number of blood vessels was found in the bone-side third of the PDL. The distal surface had the highest proportion of blood vessels, and the palatal surface the least proportion. The number of blood vessels in all surface quadrants did not vary much from three to four weeks of age, but increased from four to six weeks of age, possibly as a reaction to tooth emergence and occlusal function. Physiological root resorption was only observed after tooth emergence, and appeared to be related to loss of continuity of the ERM network and the incursion of blood vessels. Conclusions: Orthodontic root resorption can be regarded as an exaggerated response to loss of PDL homeostatic control, possibly mediated by the epithelial rests of Malassez.