The Effects Of PTHrP On Proliferation And C-fos MRNA Expression Of Human Osteoblast-like Cell Under The Circumstance Of Static Tension-force

Objective: 1. To investigate the effects of different static tension-force on PTHrP expression by human osteoblasts(MG-63) in vitro . 2. To investigate the effects of static tension-stress and PTHrP on proliferation and c-fos mRNA expression of human osteoblasts in vitro.Materials and Methods: 1. human osteoblasts were treated by tension-force values of 8% and12% for 0h,12h,24h respectively. After treatment each sample was collected and measured the expression of PTHrP by the reverse transcription-polymerase chain reaction (RT-PCR) at messenger RNA(mRNA) level. 2. The effects of static tension-stress(12%) and different PTHrP doseage ( 0-0.01-0.1-ln mol/L) on the proliferation of human osteoblasts were examined using flow cytometry. 3. The effects of static tension-force and/or PTHrP on c-fosexpression by human osteoblasts were indicated by the reverse transcription-polymerase chain reaction ( RT-PCR) at messenger RNA(mRNA) level.Results: 1. static tension-stress significantly increaseed PTHrP mRNA levels in human osteoblasts (P<0.05).Strain of 12% induced significantly more THrP mRNA than that of 8% (P<0.05). 2. The mitogenesis happened in the group with static tension-stress(12%) combined with PTHrP was more active than that in the group with PTHrP or static tension-stress only (P<0.05). static tension-stress combined with PTHrP induced significantly more c-fos mRNA than that of static tension-stress (P<0.05).Conclusion: 1. Mechanical induction of PTHrP possibly provedes the environment for rebuilding of bone. 2. The most active mitogenesis happened in the group with static tension-stress combined with PTHrP. The effect was related with the increasmg expression of c-fos.