Improving Healing by Targeting Weak Electric Fields in Wounds

    People with diabetes often suffer from wounds that are slow to heal and can lead to ulcers, gangrene, and amputation. Now, an international team led by Min Zhao, M.D., Ph.D., professor of ophthalmology and of dermatology at the University of California, Davis, has shown that, in animal models of diabetes, slow healing is associated with weaker electrical currents in wounds. The results could ultimately open up new approaches for managing diabetic patients.

    “This is the first demonstration, in diabetic wounds or any chronic wounds, that the naturally occurring electrical signal is impaired and correlated with delayed healing,” said Dr. Zhao, adding that as much as $25 billion a year is spent on treating chronic ulcers and wounds related to diabetes. “Correcting this defect offers a totally new approach for chronic and nonhealing wounds in diabetes.”

    Electric fields are associated with living tissue. Previous work by Dr. Zhao and Brian Reid, Ph.D., project scientist at the UC Davis department of dermatology, demonstrated that electric fields are associated with healing damage to the cornea of the eye. In the new study (“Diabetic Cornea Wounds Produce Significantly Weaker Electric Signals That May Contribute to Impaired Healing”), published in Scientific Reports, Drs. Zhao, Reid, and colleagues used a highly sensitive probe to measure electrical fields in the corneas of isolated eyes from three different lab mouse models with different types of diabetes—genetic, drug-induced, and mice fed a high-fat diet.

    In a healthy eye, there is an electrical potential across the thickness of the cornea. Removing a small piece of cornea collapses this potential and creates electric currents, especially at the edges of the wound. Cells migrate along the electric currents, closing the scratch wound in about 48 hours. The researchers found that these electric currents were much weaker in eyes from all three strains of diabetic mice than in healthy mice. Delayed wound healing was correlated with weaker electric currents.

    “We saw similar results with all three models,” noted Dr. Reid.

    The researchers also found that human corneal cells exposed to high levels of glucose showed less response to an electric field. Diabetics have high levels of glucose in their tears.

    One of the core strengths of the UC Davis bioelectricity laboratory is the ability to make such sensitive measurements of electric fields in living tissue. “We might be the only lab in the country that is able to do this,” pointed out Dr. Reid. The team is collaborating with a number of laboratories worldwide and across the country, as well as several other UC Davis departments.