Evaluation of the ratio of collagen type III to collagen type I in periurethral tissues of sexually intact and neutered female dogs.

OBJECTIVE: To determine the ratio of collagen type III to collagen type I in the periurethral tissues of sexually intact and neutered female dogs. ANIMALS: 8 neutered and 34 sexually intact female dogs. PROCEDURES: Tissues were obtained from female dogs euthanized for non-urinary tract-related reasons. Indirect immunofluorescent antibody detection of type I and collagen type III was performed by use of confocal microscopy on 2 periurethral samples from each dog, and the ratios of collagen type III to type I area fraction and total area were determined. RESULTS: No significant differences were detected in the collagen ratios of periurethral tissues between sexually intact and neutered female dogs. CONCLUSIONS AND CLINICAL RELEVANCE: In contrast to differences in periurethral collagen content found between pre- and postmenopausal women, such differences may not occur in dogs. This implies that changes in pelvic organ support structures may not play an important role in urinary incontinence in neutered female dogs. Further evaluation is needed to determine the role of age on collagen and pelvic organ support structures in the pathogenesis of canine urinary incontinence.