The effects of imposed electrical fields on cultured Xenopus laevis epidermal cells

Zenephia Elaina Evans, Purdue University

Abstract

Once a wound is made in the skin, the first in the sequence of events to properly heal the wound is epithelization, the movement of epithelial cells to cover the wound. This process occurs normally in most instances, but not always. It therefore is worthwhile to analyze wound healing in order to understand the process fully and thereby be able to control it. There have been many approaches to promoting wound healing, among which is the use of D.C. fields. In this study, I sought to clarify the responses epidermal cells have to imposed fields. To do this, I imposed electric fields across cultured Xenopus laevis epidermal cells, and recorded their movement by time-lapse video microscopy, tracing and digitizing. Each experiment was divided into a one-hour control phase (with no imposed field) and a three-hour experimental phase, where field strengths ranging from 10 mV/mm to 406 mV/mm were imposed on the cells. Except for 50 mV/mm, at field strengths between 20 and 80 mV/mm, the cells migrated preferentially towards the cathode (in terms of the number of cells and the distance that the cells migrated). At 10 and 100 mV/mm, there was no bias in migration, and at 200+ mV/mm field strengths, the bias was towards the anode. The threshold for a response was 20 mV/mm and the optimum response was at 40 mV/mm. Ignoring the turning behavior of the cells, the rates of migration and the directedness of migration were higher in the controls than in the experimentals. I also determined that the currents exiting Xenopus wounds are outcurrents, which is the same as in the newt. These results are generally consistent with the in vivo observations that 40 mV/mm is optimal for promoting newt wound healing, and that higher wound fields inhibit wound epithelization.

Degree

Ph.D.

Advisors

Vanable, Purdue University.

Subject Area

Anatomy & physiology|Animals|Cellular biology

COinS