Open Journal of Stomatology, 2018, 8, 53-69 http://www.scirp.org/journal/ojst ISSN Online: 2160-8717 ISSN Print: 2160-8709 Application of Hypoxic Exposure Combined with Osteogenic Induction for the Enhancement of Multiple Osteoinductive Capabilities in Rat Mesenchymal Cells Naoaki Saito 1,2,3 , Hiroko Kato 4 , Yosuke Akiba 5 , Yuko Hara 2 , Taku Kojima 1 , Michiko Yoshizawa 1 , Atsushi Ohazama 3 , Takeyasu Maeda 4 , Tadaharu Kobayashi 1 , Kenji Izumi 2* 1 Division of Reconstructive Surgery for Oral and Maxillofacial Region, Department of Tissue Regeneration and Reconstruction, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan 2 Division of Biomimetics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan 3 Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan 4 Research Center for Advanced Oral Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan 5 Division of Bio-Prosthodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan Abstract Objective: The enhancement of multiple functions, including osteogenesis, angiogenesis, and cell recruitment, is required for efficient bone regeneration therapy. Recently, special attention has been focused on the microenviron- ment of stem cells to facilitate bone regeneration. Herein, we examined the effects of various combinations of hypoxic conditions and osteogenic induc- tion on rat mesenchymal cells, to develop a specific protocol for enhancing the multiple cellular functions beneficial to bone regeneration. Methods: Rat mesenchymal cells, isolated from bone marrow, adipose tissue, and periodon- tal ligament, were examined. The cells were cultured under varied conditions of O 2 tension (hypoxia) and duration and timing of hypoxic exposure, with or without osteogenic induction. Consequently, four different protocols were ex- amined by measuring the gene expression levels of Runx2, Vegfa, and Cxcl12, indicating a capability for osteogenesis, angiogenesis, and cell recruitment, respectively. Finally, the mineralization ability of the rat mesenchymal cells was assessed by quantitating their calcified nodule formation. Results: The simul- taneous application of hypoxic exposure and osteogenic induction promoted Vegfa expression in all types of cells, but suppressed Runx2. In contrast, hy- How to cite this paper: Saito, N., Kato, H., Akiba, Y., Hara, Y., Kojima, T., Yoshizawa, M., Ohazama, A., Maeda, T., Kobayashi, T. and Izumi, K. (2018) Application of Hy- poxic Exposure Combined with Osteogenic Induction for the Enhancement of Multiple Osteoinductive Capabilities in Rat Mesen- chymal Cells. Open Journal of Stomatology, 8, 53-69. https://doi.org/10.4236/ojst.2018.82005 Received: January 2, 2018 Accepted: February 23, 2018 Published: February 26, 2018 Copyright © 2018 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access DOI: 10.4236/ojst.2018.82005 Feb. 26, 2018 53 Open Journal of Stomatology