Vieira Andreia Espindola, Repeke Carlos Eduardo, Ferreira Junior Samuel de Barros, Colavite Priscila Maria, Biguetti Claudia Cristina, Oliveira Rodrigo Cardoso, Assis Gerson Francisco, Taga Rumio, Trombone Ana Paula Favaro, Garlet Gustavo Pompermaier
Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
Department of Biological and Allied Health Sciences, Sacred Heart University, Bauru, Brazil.
PLoS One. 2015 May 29;10(5):e0128021. doi: 10.1371/journal.pone.0128021. eCollection 2015.
Bone tissue has a significant potential for healing, which involves a significant the interplay between bone and immune cells. While fracture healing represents a useful model to investigate endochondral bone healing, intramembranous bone healing models are yet to be developed and characterized. In this study, a micro-computed tomography, histomorphometric and molecular (RealTimePCRarray) characterization of post tooth-extraction alveolar bone healing was performed on C57Bl/6 WT mice. After the initial clot dominance (0 h), the development of a provisional immature granulation tissue is evident (7 d), characterized by marked cell proliferation, angiogenesis and inflammatory cells infiltration; associated with peaks of growth factors (BMP-2-4-7,TGFβ1,VEGFa), cytokines (TNFα, IL-10), chemokines & receptors (CXCL12, CCL25, CCR5, CXCR4), matrix (Col1a1-2, ITGA4, VTN, MMP1a) and MSCs (CD105, CD106, OCT4, NANOG, CD34, CD146) markers expression. Granulation tissue is sequentially replaced by more mature connective tissue (14 d), characterized by inflammatory infiltrate reduction along the increased bone formation, marked expression of matrix remodeling enzymes (MMP-2-9), bone formation/maturation (RUNX2, ALP, DMP1, PHEX, SOST) markers, and chemokines & receptors associated with healing (CCL2, CCL17, CCR2). No evidences of cartilage cells or tissue were observed, strengthening the intramembranous nature of bone healing. Bone microarchitecture analysis supports the evolving healing, with total tissue and bone volumes as trabecular number and thickness showing a progressive increase over time. The extraction socket healing process is considered complete (21 d) when the dental socket is filled by trabeculae bone with well-defined medullary canals; it being the expression of mature bone markers prevalent at this period. Our data confirms the intramembranous bone healing nature of the model used, revealing parallels between the gene expression profile and the histomorphometric events and the potential participation of MCSs and immune cells in the healing process, supporting the forthcoming application of the model for the better understanding of the bone healing process.
骨组织具有显著的愈合潜力，这涉及到骨与免疫细胞之间重要的相互作用。虽然骨折愈合是研究软骨内骨愈合的有用模型，但膜内骨愈合模型尚未得到开发和表征。在本研究中，对C57Bl/6野生型小鼠进行了拔牙后牙槽骨愈合的微型计算机断层扫描、组织形态计量学和分子（实时定量PCR阵列）表征。在最初的血凝块占主导（0小时）之后，临时未成熟肉芽组织开始发育（7天），其特征为明显的细胞增殖、血管生成和炎性细胞浸润；与生长因子（骨形态发生蛋白-2-4-7、转化生长因子β1、血管内皮生长因子a）、细胞因子（肿瘤坏死因子α、白细胞介素-10）、趋化因子及受体（CXC趋化因子配体12、CC趋化因子配体25、CC趋化因子受体5、CXC趋化因子受体4）、基质（I型胶原蛋白α1-2、整合素α亚基4、玻连蛋白、基质金属蛋白酶1a）和间充质干细胞（CD105、CD106、八聚体转录因子4、Nanog基因、CD34、CD146）标志物表达的峰值相关。肉芽组织依次被更成熟的结缔组织取代（14天），其特征为随着骨形成增加炎性浸润减少、基质重塑酶（基质金属蛋白酶-2-9）、骨形成/成熟（Runx2、碱性磷酸酶、牙本质基质蛋白1、磷酸盐调节基因同源物、硬化蛋白）标志物以及与愈合相关的趋化因子及受体（CC趋化因子配体2、CC趋化因子配体17、CC趋化因子受体2）的显著表达。未观察到软骨细胞或组织的证据，这进一步证实了骨愈合的膜内性质。骨微结构分析支持了不断演变的愈合过程，随着时间推移，总组织和骨体积以及小梁数量和厚度均呈逐渐增加趋势。当牙槽窝被具有明确髓腔的小梁骨填充时，拔牙窝愈合过程被认为完成（21天）；这是该时期成熟骨标志物普遍表达的体现。我们的数据证实了所使用模型的膜内骨愈合性质，揭示了基因表达谱与组织形态计量学事件之间的相似性以及间充质干细胞和免疫细胞在愈合过程中的潜在参与，支持该模型未来用于更好地理解骨愈合过程。
