Perspective: Normal and Abnormal Uterine Response to Sperm Deposition in the Bitch

Little is known about the response of the bitch’s reproductive tract to semen deposition. Coitus causes an increase in uterine contractions (1) and recently we have documented an influx of polymorphonuclear neutrophils (PMNs), an increase in uterine artery blood velocity and vasodilation associated particularly with uterine deposition of seminal plasma and prostatic fluid (PF). The PMN influx appears to be perturbed in healthy bitches with cystic endometrial hyperplasia, probably representing a mating-induced endometritis similar to that observed in other species. In unpublished studies we demonstrated that PMNs reduce the ability of sperm to attach to uterine epithelium and that this effect is ameliorated in the presence of PF. These studies suggest that dog accessory gland secretion has an important role in the initiation and regulation of a uterine inflammatory response to mating but as yet its clinical significance is not fully understood. [...]