Effect Of Four-point Bending Mechanical Stress On Cell Proliferation Of Human Bone Marrow Mesenchymal Stem Cells

Objective:To study the effect of mechanicaI stretch stress on proliferation of human bone marrow-derived mesenchymal stem cells(BMS Cs ) .Methods:The experiment was carned out in Laboratory of regenerative medicine centre of first affiliated hospital of dalian medical university from September 2010 to March 2011.1. BMSCs obtained by density gradient centrifugation from normal volunteers .2.A Four-Point bending (Developmented by Huaxi medical college and University of Electronic Science and Technology of China Patent No:CN2534576 and CN1425905)apparatus is utilized to perform a series of various mechanieal strain on BMSCs,4rd⁶rd generational cells were collected and cultured on the afterburner board(BD No.353135),Grouping: control group,the experimental group received 0.5HZ mechanic device and signal stimulusat different stresses 1000,3000,5000μstrain in 60 min,the control group did not receive signal stimulated by mechanical strain and other cultural conditions were the same as the experimental group.3. After BMSCs were stimulated by mechanical strain,the cellular counting by MTT, flow cytometry were applied to measure the cellular proliferation and cell cycle, Ca²⁺ flowing were measured by LSCM.4. Statistical analysis:Data are recorded as mean±standard deviation, SPSS16.0 software package for single-factor analysis and differerces were considered statistically significant at P<0.05 level and P<0.01 level.Results:1. BMSCs obtained by density gradient centrifugation is suitable and quickly.2. The Four-Point bending could be used to evaluate cells reponse sensitivity to mechanical stress in vitro. Cells were adherenced to the wall 12-24 hours after inoculated on the afterburner afterburner board.After 24 hours,the fraction of coverage reached to 80%,and no bacterial contamination.3. After appropriate force magnitude mechanicaI stretch stress treatment,BMSCs cellular proliferation had been accelerated and cellular cycle had been changed with proliferation board. After 24 hours,the fraction of coverage reached to 80%,and no bacterial contamination.3. After mechanical stretch stress treatment of appropriate force magnitude,BMSCs cellular proliferation had been inhanced and cellular cycle had been changed with proliferation index increasing.When the strain magnitude was 3000μstrain. The cellular proliferation was the most obviously enhanced after treatment. mechanical stretch stress treatment could enhance the cell proliferation.But cellular proliferation was suppressed after excessive force magnitude( 5000μstrain) .Conclusion: Mechanical stretch stress can enhance effect on the cellular proliferation of BMSCs .