OBJECTIVETo study the changes in the proliferation and synthetic function of human periodontal ligament fibroblasts (HPDLF) in response to dynamic mechanical strains of different modes, magnitudes and durations.

METHODSUsing a 4-point bending system, the effect of dynamic mechanical strains of different modes, magnitudes and durations on the proliferation of HPDLF was investigated by analyzing the cell cycle changes with flow cytometry (FCM), and the total protein level and the activity of alkaline phosphatase (ALP) in HPDLF were assayed by quantitative analysis.

RESULTSThe percentage of G(0)/G(1) cell decreased, S phase cells increased, and the proliferation index (PI), total protein level and activity of ALP were augmented significantly in response to dynamic mechanical micro-strains. These changes showed close correlations to the magnitude and duration of the strain. The mode of strain caused significant changes in G(0)/G(1), S, and G(2)/M phase cell percentages as well as the PI, total protein level and ALP activity of the cells. In the gradient strain group, the cell proliferation activity, total protein level and ALP activity were obviously higher than those in 1000 and 4000 microstrain groups.

CONCLUSIONThe changes in the proliferation and synthetic function of HPDLF are closely correlated to the mode, magnitude and duration of the strains.