Stereological analysis of the urethra in sexually intact and spayed female dogs.
The perfusion-fixed urethrae of 5 sexually intact nulliparous and 5 ovariohysterectomized beagles were analyzed stereologically. Different urethral tissue components were estimated stereologically in each of the three proximal urethral quarters and compared between the two groups of dogs. Considerable individual variability within all groups was observed. In all the three urethral quarters considered, average smooth muscle and connective tissue volumes were generally lower in spayed than in intact animals, both in absolute and relative terms. However, only the difference between the mean relative volumes of urethral quarter I was statistically significant. In contrast, mean absolute and relative volumes of the vascular plexus were generally greater in the ovariohysterectomized dogs as compared to the animals of the other group--deviations in statistical relevance concerning the first urethral quarter were noted. Mean epithelial and striated muscle volumes did not vary essentially between the spayed and intact group of dogs. Despite the fact that all findings were not always statistically meaningful, our research nevertheless demonstrates that ovariohysterectomy decreases smooth muscle mass and connective tissue; it also elevates vascular plexus volumes in the urethra of spayed animals. Moreover, our results imply a general weakening of the urethral wall as a sequel to ovariohysterectomy, and this, in turn, could be seen to affect the closure mechanism of the urethra.
Augsburger
H R
HR
Institute of Veterinary Anatomy, University of Zürich, Switzerland.
Cruz-Orive
L M
LM
D000818:Animals; D003238:Connective Tissue / Q000033:anatomy & histology; D004285:Dogs / Q000033:anatomy & histology*; D004848:Epithelium / Q000033:anatomy & histology; D005260:Female; D018482:Muscle, Skeletal / Q000033:anatomy & histology; D009130:Muscle, Smooth / Q000033:anatomy & histology; D010052:Ovariectomy / Q000009:adverse effects*; D010298:Parity; D014521:Urethra / Q000033:anatomy & histology* / Q000098:blood supply; D014549:Urinary Incontinence / Q000209:etiology