Periodontal Ligament Cells Are Involved in the Formation of Intracanal Cementum-Like Tissue After Regenerative Endodontic Procedures: A Mouse in situ Model
Periodontal Ligament Cells Are Involved in the Formation of Intracanal Cementum-Like Tissue After Regenerative Endodontic Procedures: A Mouse in situ Model
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DOI：
10.3389/fdmed.2022.864406
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发表时间：
2022-05-11
影响因子：
--
通讯作者：
Muramatsu, Takashi
中科院分区：
文献类型：
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作者：
Komada, Tomoaki;Mitomo, Keisuke;Muramatsu, Takashi
再生牙髓细胞归巢手术经常在诊断为牙髓坏死和/或根尖周炎的受伤未成熟牙齿上进行。这些手术后的代表性组织学发现是牙骨质样组织填充在根管中，但愈合过程的细节仍然未知。我们使用小鼠原位模型从组织学角度研究了愈合过程。对 6 周龄雄性 C57BL/6 小鼠未感染的上颌第一磨牙进行实验性牙髓再生手术，然后使用组织学和免疫组织化学研究愈合过程。再生牙髓细胞归巢手术后，根管内立即出现血凝块，随着时间的推移，血凝块消失了。第7天，根管内的血块被肉芽组织取代。从第14天开始，牙骨质样组织在根管内被填充，而纤维组织的数量减少。免疫组织化学显示，根管、根尖和牙周膜细胞的纤维组织中骨膜素呈阳性反应。另一方面，根管内未检测到巢蛋白阳性反应。在根尖周围的纤维组织和根管内新形成的牙骨质样组织周围也观察到具有管腔结构的CD31阳性细胞。因此，在这项研究中，我们建立了再生牙髓手术的原位小鼠模型。本研究结果表明，在再生牙髓手术的愈合过程中，牙周膜细胞和血管内皮细胞从根尖生长到根管内，取代血凝块，并参与牙骨质样组织的形成和血管生成。
Regenerative endodontic cell-homing procedures are frequently performed on injured immature teeth diagnosed with pulp necrosis and/or apical periodontitis. The representative histological finding after those procedures is cementum-like tissues filling in the root canal but details of the healing process remain unknown. We investigated that healing process histologically using a mouse in situ model. Regenerative endodontic procedures were experimentally performed on noninfected maxillary first molars of 6-week-old male C57BL/6 mice, after which the healing process was investigated using histology and immunohistochemistry. Immediately after the regenerative endodontic cell-homing procedures, blood clots were seen in the root canals that disappeared over time. On day 7, the blot clot in the root canal was replaced by granulation tissue. From day 14 onward, cementum-like tissues were filled in the root canals, while the amount of fibrous tissue was reduced. Immunohistochemically, positive reactions for periostin were seen in the fibrous tissue in the root canal, the apex, and periodontal ligament cells. On the other hand, positive reactions for nestin were not detected in the root canal. CD31-positive cells with a luminal structure were also observed in the fibrous tissue around the apex and around the newly formed cementum-like tissues in the root canal. Thus, in this study, we have established an in situ mouse model of regenerative endodontic procedures. The results of this study suggest that periodontal ligament cells and vascular endothelial cells grow into the root canals from the apex, replace the blood clots, and participate in the formation of cementum-like tissues with angiogenesis during the healing process of regenerative endodontic procedures.