Osteoblasts are bone-forming cells that are responsible for the production of bone extracellular matrix. Osteoradionecrosis is a complication of radiation therapy for carcinoma of the head and neck that occurs in 3% to 8.2% of irradiated patients. The irradiation effect on osteoblast differentiation has not been fully elucidated. The objective of our research was to elucidate the effects of radiation on the growth and differentiation-related gene expression in osteoblast in vitro. Three differentiation-related genes, alkaline phosphatase, type I collagen, and osteocalcin, were tested in our experiment. The results showed that radiation inhibited the proliferation of the osteoblasts in a dose-dependent manner and induced G2/M cell cycle arrest. Irradiation, 4 and 8 Gy, enhanced the differentiation-related gene expression of MC3T3-E1 cells 7 days after irradiation. However, the differentiation-related gene expression was decreased 21 days after irradiation in the 4- and 8-Gy groups. This work presents the dynamic phenotypic expression changes of osteoblastic cells after x-ray irradiation.
From the Departments of *Oral and Maxillofacial Surgery, and †Oral and Maxillofacial Radiology, Shanghai Jiao-tong University, School of Medicine, Shanghai Ninth People's Hospital, Shanghai, People's Republic of China.
Received June 9, 2011.
Accepted for publication July 12, 2011.
Address correspondence and reprint requests to Dr. Yue He, Zhi-zao-ju Rd, No. 639, Shanghai, People's Republic of China; E-mail: email@example.com
This study was supported by the National Natural Science Foundation of China (30600714, 30973341), Shanghai Rising-Star Program (07QA14039), and the "Shu Guang" project (10SG19).
The authors report no conflicts of interest.