The early phase response of rat alveolar bone to traumatic occlusion

Abstract

Objectives: Occlusal trauma is an important factor to influence alveolar bone remodelling, the effect of which includes many cytokines and signalling pathways. However, the exact mechanism of the traumatic stimulus for alveolar remodelling is still unclear. The purpose of the present study was to investigate the early responses of alveolar osteocytes to occlusal trauma through genome-wide microarray.

Methods: The occlusal surface of the upper left first molar of rat was raised by placing a stainless steel wire to induce occlusal trauma in the lower left first molar. After 24 h, we took out the alveolar bone tissue of the first molars at the both sides of rats' lower jaws under anaesthesia. The different gene expressions were showed by genome-wide microarray, which comprises about 27,000 genes and the results were examined by quantitative RT-PCR.

Result: Of the approximately 27,000 genes, the expression of 586 genes was strongly changed. These findings clearly demonstrated that in the early response of the alveolar bone to occlusal trauma, the expression of osteoblast, collagens, bone mineralization, bone remodelling and WNT, TGF-β pathway related cytokines decreased, and osteoclast-specific cytokines have no significant changes in expression.

Conclusion: These results suggested that at early phase of the occlusal trauma, osteogenesis in rat's alveolar bone was inhibited, and osteoclastogenesis was not significant.