Isolation of Matrix Vesicles associating with Dentinogenesis and Application for Pulpotomy

牙本质发生相关基质囊泡的分离及其在活髓切断术中的应用

• 批准号: 60480414
• 负责人: NAGASAWA Hisashi
• 金额: $ 4.42万
• 依托单位: Kyushu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-60480414/
• 关键词: Dentinogenesis; Matrix Vesicles; 生活歯髄切断法

Matrix vesicles are involved in the early stages of the mineralization process, and it now seems to be generally agreed that they are sites of initial crystal formation. Present study was carried out to isolate these vesicles during initial dentinogenesis and to investigate the application for pulpotomy.Apical pulps of Wistar rats were excised with a razor blade. Small slices of them were incubated with collagenase. Pulp digest was centrifuged. Fractions were obtained as follows : (1) 40,000 x g for 20 min ; (2) 300,000 x g for 10 min. Electron microscopy of the centrifugal sediments showed intact cells and cell fragments, and partially fragmented endoplasmic reticulum in fraction 1. Vesicles closely resembling the matrix vesicles, because of their small size, electron-dense contents, were concentrated in the 2nd fraction. The specific activity for alkaline phosphatase was 4.57 <+!-> 0.76 U. Total protein contents were 0.73 <+!-> 0.10 <mu> g /mg wet weight. Needle-like crystals did not grow within matrix vesicles in Ca・P solution containing ATP ( 2 - 5 h, 37゜C ).These results indicate that matrix vesicles first isolated from dental pulp has biological activity and similar fine structure to that of in vivo ones. Further study would be necessory to form the hydroxyapatite in matrix vesicles in vitro; the contents of incubation medium and culture condition might be decisive factors. This future investigation could catch the basic data to applicate these vesicles for pulpotomy.

基质囊泡参与了矿化过程的早期阶段，现在似乎普遍认为它们是初始晶体形成的场所。本研究在牙本质形成初期分离这些囊泡，并探讨其在牙髓切开术中的应用。用刀片切除Wistar大鼠的根尖髓。将它们的小片与胶原酶孵育。对果肉进行离心消化。所得馏分如下：(1)40000 x g，静置20 min；(2) 300,000 x g静置10分钟。离心沉积物的电镜显示完整的细胞和细胞碎片，部分内质网部分破碎。囊泡与基质囊泡非常相似，由于其体积小，电子密度大，主要集中在第二部分。对碱性磷酸酶的比活性为4.57 <+！-> 0.76 u总蛋白含量0.73 <+！-> 0.10 <mu> g /mg湿重。针状晶体在含有ATP的Ca·P溶液中不能在基质囊泡内生长（2 - 5小时，37 C）。上述结果表明，首次从牙髓中分离得到的基质囊泡具有生物活性，其精细结构与体内基质囊泡相似。羟基磷灰石在基质囊泡中的体外形成有待进一步研究；培养培养基的含量和培养条件可能是决定因素。今后的研究将为这些囊泡在切髓术中的应用提供基础资料。