Figure 1.

Continuous compressive force–induced [Ca²⁺]_i responses in human fibroblasts in intact PDL explants. A) Schematic diagram of the delivery of continuous compressive force to intact hPDL explants. B) The double-labeled fluorescence and interference contrast microscope (DIC) images of hPDL fibroblasts in intact explants tagged with Fluo8 (green). C) Individual color lines represent the cells. D) Serial pseudocolor images of the hPDL fibroblasts in B at 0, 114, 150, and 276 s after the initiation of monitoring. The vertical color scale represents relative fluorescence intensity. Arrowhead indicates [Ca²⁺]_i response. A movie of the serial pseudocolor images can also be seen in the supplemental data (Supplemental Video S1). E) Representative traces of [Ca²⁺]_i dynamics in individual hPDL fibroblasts in intact explants following continuous compressive force. The elevation of the relative fluorescence intensity was defined by the mean intensity observed before the application of compressive force. F) The percentage of responsive cells, peak relative fluorescence intensity in the responsive cells, and cell response frequency in the responsive cells after the continuous compressive force was calculated. The data are expressed as the means ± sd. Scale bars, 20 µm. The asterisks indicate significant differences; **P < 0.01: paired Student’s t test.