ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of parathyroid hormone related protein (PTHrP) on proliferation of human osteoblasts (MG-63) under the circumstance of tension force in vitro.</p><p><b>METHODS</b>An apparatus was designed and fabricated by which force was loaded onto the cultured cells in vitro. Reverse transcription-polymerase chain reaction (RT-PCR) was used for measuring the expression of PTHrP mRNA and c-fos mRNA. The effect of tension force and different PTHrP dose(0, 0.01, 0.1, 1 nmol/L) on the proliferation of human osteoblasts were examined using flow cytometry.</p><p><b>RESULTS</b>Various forces of the mechanical stretching exerted different influences on the intensities of the mRNA' expression. The strain of 12% induced the most remarkable mRNA' expression. The mitogenesis happened in the group with tension force (12%) combined with PTHrP was more active than that in the group with PTHrP or tension' force only. Tension force combined with PTHrP induced significantly more c-fos mRNA than that of tension force only.</p><p><b>CONCLUSION</b>The mechanical stretching can inevitably influence the expression of PTHrP mRNA. The most active mitogenesis happened in the group with tension force combined with PTHrP. The effect may be related with the signaling pathways of c-fos.</p>
Subject(s)
Humans , Cell Line , Cell Proliferation , Cells, Cultured , Osteoblasts , Parathyroid Hormone-Related Protein , RNA, MessengerABSTRACT
OBJECTIVE@#To determine the effect of continuously compressive pressure (CCP) on the expression of receptor activator of nuclear factor kappa B ligand (RANKL) in human periodontal ligament cells (HPDLCs) and to investigate the role of RANKL in alveolar bone rebuilding during orthodontic tooth movement.@*METHODS@#The primary HPDLCs were isolated from human periodontal ligament by explanting enzymatic digestion with trypsin and collagenase to establish a pressure model. Top-bottom axial pressures (1, 2, and 3 g/cm(2)) were laid on HPDLCs for 0.5, 1.5, 6, 12, 24, and 48 h, respectively. The RANKL expression was identified by the reverse transcription-polymerase chain reaction (RT-PCR) at the mRNA level.@*RESULTS@#The expression of RANKL mRNA significantly increased in a time-dependent manner (P<0.01), so did the value of pressure, especially in the 2 g/cm(2) group (P<0.05).@*CONCLUSION@#CCP can up-regulate the expression of RANKL mRNA in human periodontal ligament cells.