Mapping of BrdU label-retaining dental pulp cells in growing teeth and their regenerative capacity after injuries
Mapping of BrdU label-retaining dental pulp cells in growing teeth and their regenerative capacity after injuries
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DOI：
10.1007/s00418-010-0727-5
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发表时间：
2010-09-01
影响因子：
2.3
通讯作者：
Ohshima, Hayato
中科院分区：
文献类型：
--
作者：
Ishikawa, Yuko;Ida-Yonemochi, Hiroko;Ohshima, Hayato
最近的研究表明，人类牙髓中含有成体干细胞。在最佳时间给予年轻动物胸苷类似物BrdU的脉冲可以澄清缓慢循环的长期标记保留细胞（LRC），推定的成体干细胞，驻留在牙髓组织中。本研究的重点是LRC在生长牙齿和牙齿损伤后的再生能力的映射。2 - 7次BrdU腹腔注射到怀孕的Wistar大鼠中，发现出生动物的成熟组织中存在缓慢循环的长期致密LRC。大量致密的LRC在出生后数量减少，在出生后4周达到平台期，主要位于牙髓中心，与血管相连。成熟牙髓细胞用Hoechst 33342染色，并使用FACS分选成（< 0.76%）侧群细胞，其包括致密的LRC。一些致密的LRC共表达间充质干细胞标志物，如STRO-1或CD 146。牙齿损伤引起成牙本质细胞层的退化，新分化的成牙本质细胞样细胞含有LRC。因此，成熟牙髓组织中致密的LRC被认为是牙髓干细胞，具有形成新分化的成牙本质细胞样细胞的再生能力。本研究提出了一个新的假说，即牙髓中既有颗粒状LRC，也有致密型LRC，具有增殖能力的致密型LRC在外源性刺激后的牙髓愈合过程中与颗粒状LRC协同发挥重要作用。
Recent studies have demonstrated that human dental pulp contains adult stem cells. A pulse of the thymidine analog BrdU given to young animals at the optimal time could clarify where slow-cycling long-term label-retaining cells (LRCs), putative adult stem cells, reside in the pulp tissue. This study focuses on the mapping of LRCs in growing teeth and their regenerative capacity after tooth injuries. Two to seven peritoneal injections of BrdU into pregnant Wistar rats revealed slow-cycling long-term dense LRCs in the mature tissues of born animals. Numerous dense LRCs were postnatally decreased in number and reached a plateau at 4 weeks after birth when they mainly resided in the center of the dental pulp, associating with blood vessels. Mature dental pulp cells were stained with Hoechst 33342 and sorted into (< 0.76%) side population cells using FACS, which included dense LRCs. Some dense LRCs co-expressed mesenchymal stem cell markers such as STRO-1 or CD146. Tooth injuries caused degeneration of the odontoblast layer, and newly differentiated odontoblast-like cells contained LRCs. Thus, dense LRCs in mature pulp tissues were supposed to be dental pulp stem cells possessing regenerative capacity for forming newly differentiated odontoblast-like cells. The present study proposes the new hypothesis that both granular and dense LRCs are equipped in the dental pulp and that the dense LRCs with proliferative capacity play crucial roles in the pulpal healing process following exogenous stimuli in cooperation with the granular LRCs.