Effects of epididymal sperm recovery methods on fresh and frozen-thawed sperm characteristics in dogs

The cauda epididymis holds a collectible source of fertile spermatozoa in cases of obstructive azoospermia, sudden death, and after elective or emergency castration. The current study was conducted to compare three different epidydimal sperm collection methods (Percutaneous epididymal sperm aspiration (PESA), microsurgical epididymal sperm aspiration (MESA) and retrograde epididymal wash (EW)) in the dog. Fifteen large-breed adult dogs were applied for comparing the PESA (left testicles) with MESA (right testicles) techniques, while five dogs were used for evaluation of MESA (left testicles) versus EW (right testicles). The recovered sperm cells from MESA and EW were subjected to cryopreservation. Total sperm recovery, level of blood contamination and sperm quality markers (viability, morphology, plasma and acrosome membrane integrity, DNA fragmentation, and metabolic activity) were evaluated for fresh and frozen-thawed spermatozoa. We showed that the collection of epididymal sperm cells through the PESA method resulted in lower total sperm recovery and significantly reduced fresh sperm kinematic and quality measures. While, both MESA and EW procedures resulted in a high number of intact epididymal spermatozoa with appropriate cryo-tolerance potential. In conclusion, EW and MESA methods provide high-quality epidydimal spermatozoa with high cryopreservation potential in domestic dogs.