Effect of therapeutic ultrasound on the healing of full-thickness excised skin lesions.

The effect of therapeutic ultrasound on the healing of the dermis of full-thickness excised lesions made in the flank skin of adult rats was assessed quantitatively by means of differential cell counts made in sections of the wound bed five and seven days after injury. Wounds were either sham-treated (control group) or exposed to pulsed ultrasound (2 ms on, 8 ms off) at an intensity of 0.1 W cm-2 SATA (frequency either 0.75 MHz or 3.0 MHz). By five days after injury, ultrasound-treated wounds contained more extensive granulation tissue, fewer polymorphonuclear leucocytes (polymorphs) and macrophages, and more fibroblasts (aligned in a manner conducive to efficient wound contraction) than the sham-irradiated controls. By seven days after injury there was no significant difference in cellularity between the controls and the ultrasonically-irradiated wounds. The results obtained suggest that ultrasound therapy can be useful in accelerating the inflammatory and early proliferative stages of repair.