A preliminary study of transabdominal ultrasonic wave treatment on the germinal tissues of dog ovaries as a contraceptive approach

•Transabdominal targeting of left ovary was performed by ultransonic therapy waves.•The ultrasound waves could not completely destroy the germinal layer of the ovary during a two-month following-up.•Therapeutic ultrasound waves did not affect the kidney function. The aim of this study was to investigate effects in dogs of ultrasonic waves on the ovarian germinal tissues. There was assignment of ovaries of each dog being a control (right ovary) or treated (left ovary) tissue, regardless of the estrous cycle status. For the treated ovary, the ultrasonic probe was set at a frequency of 1 MHz and power of 1.5 W/cm2 and placed on the skin at a location in close proximity to the left ovary that was predetermined using ultrasonography. Subsequently there was a focusing of the waves for 5 min on the tissues of the treated ovary. The treatment was repeated three times at 48 -h intervals. There was placement of the probe at the same proximity to the control ovary; however, the probe was not activated. Ovariectomies for histological examination were performed 30 (five dogs) and 60 (five dogs) days following the ultrasonic treatments. Histopathological examination results indicated there was a reduction in numbers of primordial follicles of four dogs and oocyte degeneration in the Graafian and primordial follicles of five dogs. In most dogs, the degeneration of the granulosa cells of the Graafian follicle was observed in the treated ovaries. The results indicate the treatment of ovaries with transabdominal ultrasonic waves at a 1 MHz frequency, and 1.5 W/cm2 power for three times with each treatment lasting for 5 min at a 48-h interval, did not result in complete ablation of the germinal tissues of the ovary during the 2-month period subsequent to treatment.