Therapeutic ultrasound and wound closure: lack of healing effect on x-ray irradiated wounds in murine skin

Objective: To evaluate the efficacy of ultrasonography as a therapeutic agent in wound healing.

Design: Randomized, controlled trial.

Setting: University animal laboratory.

Animals: Male BALB/c mice randomly allocated to 5 groups.

Interventions: In group 1, mice were left untreated; in groups 2 through 5, a well-defined area on the dorsum was exposed to 20Gy x-ray irradiation. Seventy-two hours postirradiation, all mice were anesthetized by inhalation (isoflurane anesthetic) and a 7 x 7mm area wound made on the dorsum. All wounds were videotaped alongside a marker scale 3 times weekly until closure was complete. Mice in groups 4 and 5 were treated with pulsed therapeutic ultrasound for 5 minutes, 3 times weekly at 1 and 3MHz, respectively (intensity, 0.5W/cm(2)); mice in group 3 received placebo ultrasound. Subsequently, the area of each wound was measured from video by using an image analysis system.

Main outcome measure: Wound closure as a fraction of day zero.

Results: Irradiation caused a significant (p < .01) delay in the rate of wound closure by day 11. However, neither placebo ultrasound nor treatment at 1 or 3MHz affected the closure rate.

Conclusion: These findings provide little evidence that 1 or 3MHz ultrasound applied to a radiation-impaired wound stimulates wound closure in mice.