Possible role of superoxide dismutase 3 in hypoxia-induced developmental defects in murine molars

Yeming Lu; Yukiho Kobayashi; Yuki Niki; Keiji Moriyama

doi:10.1016/j.job.2024.100611

Possible role of superoxide dismutase 3 in hypoxia-induced developmental defects in murine molars

J Oral Biosci. 2024 Dec 31:100611. doi: 10.1016/j.job.2024.100611. Online ahead of print.

Authors

Yeming Lu¹, Yukiho Kobayashi², Yuki Niki¹, Keiji Moriyama¹

Affiliations

¹ Department of Maxillofacial Orthognathics, Division of Maxillofacial and Neck Reconstruction, Graduate School of Medical and Dental Sciences, Institute of Science Tokyo, 1-5-45, Bunkyo-ku, Tokyo, 113-8549, Japan.
² Department of Maxillofacial Orthognathics, Division of Maxillofacial and Neck Reconstruction, Graduate School of Medical and Dental Sciences, Institute of Science Tokyo, 1-5-45, Bunkyo-ku, Tokyo, 113-8549, Japan. Electronic address: yukimort@tmd.ac.jp.

PMID: 39746510
DOI: 10.1016/j.job.2024.100611

Abstract

Objectives: To investigate the effects of hypoxia on tooth germ development in mice and explore the underlying mechanisms.

Methods: Tooth germs were extracted from E14.5 mouse embryos and divided into the control and hypoxia groups for organ culture. The hypoxia group was exposed to hypoxia (0% oxygen) for 3 h, followed by normoxia for 21 h. After 2 or 7 days, samples were collected for morphometric analysis, reverse transcription-quantitative polymerase chain reaction, immunohistochemistry (IHC), and immunofluorescent staining (IF). Additionally, superoxide dismutase 3 (SOD3) expression patterns in mandibular molar tooth germs from C57BL/6 mouse embryos were analyzed using IHC. The SOD inhibitor sodium N, N-diethyldithiocarbamate trihydrate (DETC; 400 μM) was applied under normoxia for 3 days, followed by morphometry, IHC, and IF.

Results: After 7 days, the hypoxia group exhibited significantly smaller tooth size, fewer cusps, reduced cell proliferation, and increased apoptosis in the epithelium compared to the control group. Sod3 mRNA expression was higher than other Sod family member expressions in the control group. In the hypoxia group, Sod3 mRNA and SOD3 protein expression were significantly decreased, whereas hypoxia-inducible factor-1 expression and reactive oxygen species levels were increased. SOD3 was primarily expressed in the dental epithelium from E12.5 to E17.5. DETC impaired tooth germ development in the control group, resulting in a phenotype similar to that of the hypoxia group, and significantly reduced amelogenin and msh homeobox 2 expression in the epithelium.

Conclusions: Hypoxia impairs tooth germ development. SOD3 probably plays a protective role during this process.

Keywords: Hypomineralization; Hypoxia; Reactive oxygen species; Superoxide dismutase 3; Tooth development.