Expression of alkaline phosphatase in immortalized murine cementoblasts in response to compression-force.

OBJECTIVE To determine the effect of compression-force on the expression of alkaline phosphatase (ALP), and ALP activity in cementoblasts. METHODS We performed this study in the State Key Laboratory of Oral Diseases, West China Stomatology Hospital, Sichuan University, Chengdu, Sichuan, China from October to December 2010. We exposed murine immortalized cementoblasts (OCCM-30) to 2000-ustrain compression-force at a frequency of 0.5 Hz for 1, 3, 6, 12, and 24 hours. We assayed the cellular ALP activity after the treatments. We used real-time polymerase chain reaction (RT-PCR) and western blot to examine the gene and protein expression of ALP in the OCCM-30 cells at each time point. RESULTS Two-thousand ustrain compressive force significantly up-regulated the mRNA expression of ALP in OCCM-30 cells, which reached a peak at 12 hours loading, and the protein expression change of ALP in response to compression-force was consistent with the variation of gene level. We also noted marked enhancement of ALP activity in OCCM-30 cells during the application of mechanical stress. CONCLUSION The compression-force increased the expression of ALP in OCCM-30 cells, suggesting that mechanical stimulation may affect the cellular function of cementoblasts by regulating ALP expression, which may participate in cementum metabolism during orthodontic tooth movement.