Expression of MMP-13 in osteoblast cells and rat tibia after exposure to gamma rays or accelerated carbon ions

Sawajiri, M.; Takinami, S.; Uchida, T.; Nomura, Y.; Mizoe, J.; Banik, S.; Tanimoto, K.

doi:10.1016/j.ejmp.2007.03.005

« Previous Next »Physica Medica: European Journal of Medical Physics
Volume 23, Issue 2 , Pages 73-79, June 2007

Expression of MMP-13 in osteoblast cells and rat tibia after exposure to gamma rays or accelerated carbon ions

M. Sawajiri
- Department of Oral and Maxillofacial Radiology, Hiroshima University Hospital, 2–3 Kasumi-1, Minami-ku, 734-8553 Hiroshima, Japan
- Corresponding author.
S. Takinami
- Graduate School of Dental Medicine, Hokkaido University, Hokkaido, Japan
T. Uchida
- Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
Y. Nomura
- Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
J. Mizoe
- Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan
S. Banik
- Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
K. Tanimoto
- Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan

Received 28 October 2006; received in revised form 26 January 2007; accepted 22 March 2007. published online 21 May 2007.

Abstract

In past research, we found that carbon ion irradiation increased bone volume in rats, and a significant amount of cartilage remained inside the carbon ion-irradiated trabeculae. The amounts of matrix metalloproteinase 13 (MMP-13) mRNA in osteoblast-like MC3T3-E1 cells tended to decrease after carbon ion irradiation. The level of MMP-13 mRNA in non-irradiated cells was stable during the experimental period, but in gamma ray-irradiated cells it tended to increase. When localization of MMP-13 in locally irradiated experimental rats was investigated, it was found in the marginal trabeculae in both non-irradiated and gamma ray-irradiated animals. MMP-13 was detected in osteoid and neogenetic bone in the trabeculae surface. The trabeculae in carbon ion-irradiated bone remained cartilaginous. Carbon ion-irradiated rats exhibited weak expression of MMP-13 around the cartilage inside the trabeculae. We conclude that carbon ion irradiation reduced expression of MMP-13, thus suppressing both chondrocyte maturation and cartilage resorption. Increases in hyperplasia of the bone trabeculae and of bone volume were caused by ongoing bone addition and calcification in the absence of sufficient cartilage resorption.

Keywords: Carbon ion, Osteoblast, Cartilage, MMP-13