Cementocyte alterations associated with experimentally induced cellular cementum apposition in hyp mice

Autor(es):Mostrar menos -

Lira dos Santos, Elis J. ^{[1, 2]} ; Salmon, Cristiane R. ^{[2, 3]} ; Chavez, Michael B. ^[1] ; de Almeida, Amanda B. ^[2] ; Tan, Michelle H. ^[1] ; Chu, Emily Y. ^[4] ; Sallum, Enilson A. ^[2] ; Casati, Marcio Z. ^[2] ; Ruiz, Karina G. S. ^[2] ; Kantovitz, Kamila R. ^[5] ; Foster, Brian L. ^[1] ; Nociti Junior, Francisco H. ^{[2, 6]}

Afiliação do(s) autor(es)

^[1] Ohio State Univ, Coll Dent, Div Biosci, Columbus, OH 43210 - USA

^[2] Univ Estadual Campinas, Piracicaba Dent Sch, Div Periodont, Dept Prosthodont & Periodont, Ave Limeira 901, BR-13414903 Sao Paulo - Brazil

^[3] N Sra Patrocinio Univ Ctr, Fac Dent, Sao Paulo - Brazil

^[4] NIAMSD, NIH, Bethesda, MD 20892 - USA

^[5] Sao Leopoldo Mand Res Ctr, Dept Dent Mat, Campinas - Brazil

^[6] Sao Leopoldo Mand Res Ctr, Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Periodontology; v. 92, n. 11, p. 116-127, NOV 2021.
• Citações Web of Science: 1

Resumo

Background Cellular cementum, a mineralized tissue covering apical tooth roots, grows by apposition to maintain the tooth in its occlusal position. We hypothesized that resident cementocytes would show morphological changes in response to cementum apposition, possibly implicating a role in cementum biology. Methods Mandibular first molars were induced to super-erupt (EIA) by extraction of maxillary molars, promoting rapid new cementum formation. Tissue and cell responses were analyzed at 6 and/or 21 days post-procedure (dpp). Results High-resolution micro-computed tomography (micro-CT) and confocal laser scanning microscopy showed increased cellular cementum by 21 dpp. Transmission electron microscopy (TEM) revealed that cementocytes under EIA were 50% larger than control cells, supported by larger pore sizes detected by micro-CT. Cementocytes under EIA displayed ultrastructural changes consistent with increased activity, including increased cytoplasm and nuclear size. We applied EIA to Hyp mutant mice, where cementocytes have perilacunar hypomineralization defects, to test cell and tissue responses in an altered mechanoresponsive milieu. Hyp and WT molars displayed similar super-eruption, with Hyp molars exhibiting 28% increased cellular cementum area versus 22% in WT mice at 21 dpp. Compared to control, Hyp cementocytes featured well-defined, disperse euchromatin and a thick layer of peripherally condensed heterochromatin in nuclei, indicating cellular activity. Immunohistochemistry (IHC) for cementum markers revealed intense dentin matrix protein-1 expression and abnormal osteopontin deposition in Hyp mice. Both WT and Hyp cementocytes expressed gap junction protein, connexin 43. Conclusion This study provides new insights into the EIA model and cementocyte activity in association with new cementum formation. (AU)

• Processo FAPESP: 15/06372-2 - Determinação do papel dos cementócitos na homeostasia do cemento dental
• Beneficiário: Francisco Humberto Nociti Junior
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 19/09435-6 - Determinação do papel dos cementócitos na homeostasia do cemento dental durante movimentação ortodôntica
• Beneficiário: Elis Janaína Lira dos Santos
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado