ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of different kinds of mechanical stress on the mRNA expression of integrin beta1 subunit in cultured human periodontal ligament fibroblasts (hPDLF).</p><p><b>METHODS</b>To scalp and remove the periodontal ligament attached to the mid-third part of the fresh root of young premolars extracted for the cause of orthodontics. Cultured hPDLF by the method of digesting by I-type collagenase combining with tissue adhering. Then hPDLF was isolated and purified by cells passage. The sixth passage's cells were selected to be loaded. A new cyclic strain loading apparatus. Forcel four point bending device was used for mechanically loading. Cells were loaded by three levels (1000, 2000, 4000 microstrain) of tensional and compressive forces and collected at different times (0, 0.5, 1, 4, 8, 12 h) course after strain loading. The quantity of integrin beta1 mRNA in every group was analyzed by means of quantitative real-time PCR with the special primers of up- and down-regulated genes.</p><p><b>RESULTS</b>Dynamic mechanical forces down-regulated the expression of integrin beta1 subunit mRNA in hPDLF and the difference in groups by different magnitude, different kinds, and different time of mechanical forces loading were statistically significant. The stronger stimulated forces, the more down-regulated expression. Compression down-regulated the expression of integrin beta1 subunit mRNA more than tension did.</p><p><b>CONCLUSION</b>Dynamic mechanical forces could regulate the expression of integrin beta1 subunit mRNA. The difference among all the groups by different magnitudes, different kinds, and different time of mechanical forces loading were statistically significant.</p>
Subject(s)
Humans , Cells, Cultured , Fibroblasts , Integrin beta1 , Periodontal Ligament , RNA, Messenger , Stress, MechanicalABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of different dynamic tensional and compressive stress on the mRNA expression of collagen type I and fibronectin in cultured human periodontal ligament fibroblasts (hPDLF), and explore the regularity of functional change in hPDLF.</p><p><b>METHODS</b>A new cyclic strain loading apparatus was used for mechanically loading. Cells cultured in vitro were loaded with three levels (1000 microstrain, 2000 microstrain, 4000 microstrain) of tensional and compressive forces and collected at different time (0 h, 0.5 h, 1 h, 4 h, 8 h,12 h) course after strain loading. The quantity of collagen type I and fibronectin mRNA was analyzed by means of quantitative real-time PCR with special primers of up- and down-regulated genes. Data were analyzed using SPSS version 10.0 software.</p><p><b>RESULTS</b>Different magnitude and different kinds of mechanical forces as well as the force application time significantly changed the expression of collagen type I and fibronectin mRNA in hPDLF.</p><p><b>CONCLUSIONS</b>Dynamic mechanical forces could regulate the expression of collagen type I and fibronectin mRNA in hPDLF. Collagen type I and fibronectin participated in the mechanical signal transduction in human periodontal ligament fibroblasts.</p>