Electric fields and proliferation in a chronic wound model.
A wound model for decubitus and leg ulcers consisting of human dermal fibroblasts in type I collagen dermal "equivalent" matrix (DEM) was exposed in vitro to electric fields similar to postulated endogenous fields in wounds. After an 8-10 day maturation period, conductivity of DEM samples was determined. Then, DEM samples were mounted in oval windows equidistant between Ag/AgCl agar electrodes in exposure chambers containing serum-free medium. A known low-frequency sinusoidal current was then applied for 12 h, and the average electric field amplitude was calculated in the region of the cells. After a 6 h hiatus, 3H-thymidine was introduced for 6 h. This was followed by assay. Over a series of trials, field amplitude ranged from 18 to 1,000 mV/m at frequencies of 10 and 100 Hz. Proliferation was measured by total DNA and 3H-thymidine incorporation. Results indicated that a narrow amplitude window between 37 and 50 mV/meter at 10 Hz yielded increases in proliferation: At maximum (41 mV/m), there was a 70% increase in total DNA (P < .01). Increases occurred in 3H-thymidine incorporation at 41-50 mV/m but not at other amplitudes (P < .05). Increases in total DNA at 41 mV/m occurred at 10 Hz but not 100 Hz (P < .01). 3H-thymidine incorporation was in agreement (P < .05). Response was also a function of cell density within matrix. Proliferation occurred in the same amplitude and frequency ranges in which endogenous fields are expected to occur.
Goldman
R
R
Department of Rehabilitation Medicine, University of Pennsylvania, Philadelphia 19104, USA.
Pollack
S
S
D002452:Cell Count; D002455:Cell Division; D002478:Cells, Cultured; D003094:Collagen / Q000502:physiology; D016895:Culture Media, Serum-Free; D004247:DNA / Q000032:analysis / Q000378:metabolism; D015194:Diffusion Chambers, Culture; D004553:Electric Conductivity; D004599:Electric Stimulation Therapy; D004560:Electricity; D004566:Electrodes; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D006801:Humans; D007871:Leg Ulcer / Q000628:therapy; D008954:Models, Biological; D003668:Pressure Ulcer / Q000628:therapy; D018030:Silver Compounds; D012867:Skin / Q000166:cytology / Q000293:injuries; D012879:Skin Physiological Phenomena; D013936:Thymidine / Q000378:metabolism; D014316:Tritium; D014945:Wound Healing
D016895:Culture Media, Serum-Free; D018030:Silver Compounds; D014316:Tritium; D003094:Collagen; D004247:DNA; C037548:silver chloride; D013936:Thymidine