Dynamic changes in traction forces with DC electric field in osteoblast-like cells.
Primary bovine osteoblasts and human osteosarcoma cells exposed to direct-current electric fields undergo processes of retraction and elongation ultimately resulting in the realignment of the long cellular axis perpendicular to the electric field. The time taken for this reorientation was inversely correlated to field strength within a certain range. Cellular force output during reorientation was analyzed using a simple modification of traction force microscopy. The first detectable reaction was an increase in average traction force magnitude occurring between 10 and 30 seconds of electric field exposure. In the following 2 to 15 minutes traction forces at margins tangential to the electric field decreased below their initial values. Phase-contrast microscopy revealed elongating protrusions at these margins several minutes later. We could not correlate the initial traction changes with any change in intracellular free calcium levels measured using the fluorescent dye Fura-2 AM.
Curtze
Sami
S
Department of Experimental Orthopedics and Biomechanics, Philipps-University Marburg, Baldingerstrasse, 35033 Marburg, Germany.
Dembo
Micah
M
Miron
Miguel
M
Jones
David B
DB
D000180:Acrylic Resins / Q000378:metabolism; D000818:Animals; D001859:Bone Neoplasms / Q000473:pathology; D002118:Calcium / Q000032:analysis; D002417:Cattle; D002465:Cell Movement; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D004558:Electric Stimulation; D004574:Electromagnetic Fields; D004594:Electrophysiology / Q000379:methods*; D005456:Fluorescent Dyes; D016257:Fura-2; D006801:Humans; D007700:Kinetics; D018625:Microscopy, Atomic Force; D008856:Microscopy, Fluorescence; D008858:Microscopy, Phase-Contrast; D010006:Osteoblasts / Q000166:cytology* / Q000502:physiology*; D012516:Osteosarcoma / Q000473:pathology; D013379:Substrate Specificity; D014407:Tumor Cells, Cultured; D000099166:Polyacrylamides
D000180:Acrylic Resins; D002118:Calcium; D003094:Collagen; D005456:Fluorescent Dyes; D016257:Fura-2; D000099166:Polyacrylamides