The effects of lateral wound fields on healing in the newt and in the bovine cornea

Drina Diaz Sta Iglesia, Purdue University

Abstract

To clarify the role of the endogenous electric fields in wound healing, I examined re-epithelization in wounds whose field strengths were maintained at levels different from normal. In the newt, epithelization was fastest in fields with normal strengths. Increasing the normal strength by less than 50%, with externally supplied current resulted in a slight but non-statistically significant enhancement in healing, while augmenting the fields by 50% retarded epithelization. Increasing the strength to 20, 40, 60 mV/mm in lesions with fields nullified by benzamil also resulted in increased healing, with maximal healing at 40 mV/mm (the usual normal wound field strength). Fields augmented to 80 mV/mm and beyond decreased epithelization significantly. Increasing Na$\sp+$ concentration from 1.5 mM, the normal pond water concentration, to 10 mM in the medium surrounding the digits caused the field strengths to increase and epithelization to decrease. When field strengths in 10 mM Na$\sp+$ were diminished to levels found in contralateral digits at 1.5 mM by the application of direct current, the rate of epithelization was restored to normal. In the bovine cornea, decreasing the normal field strengths of $-$29 mV/mm by immersion of the lesions, or by the exposure of the lesions to benzamil, resulted in a decreased rate of wound healing. Enhancing the fields with the addition of direct current to benzamil-treated lesions caused a stepwise increase in healing rates where fields were raised to $-$60 to $-$80 mV/mm, with maximum enhancement at $-$80 mV/mm. Healing was no longer enhanced at much higher field strengths, but enhanced healing was also seen in lesions whose field strengths were raised to 80 mV/mm (in the opposite polarity). In both systems, increasing the field strengths beyond a certain strength caused healing to be retarded. They differ in that healing is maximum at field strengths at or close to normal in the newt, but at fields approximately 100% higher than normal in the bovine cornea. Healing was also enhanced in fields with reverse polarity in the bovine cornea, which was not seen with the newt skin wounds.

Degree

Ph.D.

Advisors

Vanable, Purdue University.

Subject Area

Anatomy & physiology|Animals|Biophysics|Cellular biology

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