Influence of ovariohysterectomy and deslorelin acetate on the spontaneous activity of the rabbit urinary bladder in vitro

Abstract

Lower urinary tract symptoms are not only a serious health problem but also a substantial sociologic issue affecting human beings and companion animals. Estrogen deficiency is considered an etiologic factor of urinary incontinence in postmenopausal women and spayed female dogs. However, insufficient effectiveness of hormonal therapy has caused an intensive search for new therapeutic options. GnRH analogs have positive clinical effects in neutered female dogs suffering from incontinence, but the mechanism of action is not known. The aim of our study was to determine the effect of long-acting deslorelin acetate on the spontaneous activity of urinary bladder sections from a rabbit model of long-term estrogen deprivation. The study was conducted on 21 female New Zealand White rabbits divided into the following groups: control group, ovariohysterectomized (OHX) group, and ovariohysterectomized group given a deslorelin acetate implant. Urinary bladders were excised immediately after sacrifice, and the spontaneous activity of dorsal and ventral strips of the bladder body was examined in organ bath chambers. The amplitude and frequency of the spontaneous contractions were evaluated. Most of the sections developed spontaneous activity. Ovariohysterectomy caused a decrease in the amplitude of spontaneous contractions of the tissues obtained only from the dorsal part of the bladder body. After OHX, the frequency was higher compared with the control group in both parts of the bladder. Deslorelin acetate did not significantly affect the spontaneous contraction amplitude but caused a decrease in the frequency in the dorsal and ventral parts of the bladder. In conclusion, long-term changes in the levels of hormones and other regulatory substances associated with the reproductive system are related to altered spontaneous activity of the urinary bladder, which may impact the symptoms of urgency and incontinence appearing in women after menopause and in female animals after gonadectomy. However, long-acting deslorelin acetate partially reverses the effect of OHX on the spontaneous activity of the bladder. This process might underlie the positive effects of GnRH analogs in incontinent spayed female dogs.

Keywords: GnRH analog; Ovariectomy; Rabbit; Spontaneous activity; Urinary bladder; Urinary incontinence.