Detection and Localisation of Aquaporins 1, 7 and 11 in Fresh and Frozen–Thawed Canine Epididymal Spermatozoa

Aquaporins are specific water channels that mediate the movement of water and cryoprotectants across the spermatozoa plasma membrane. The aim was to assess the presence and location of AQP1, AQP7 and AQP11 in fresh and frozen-thawed canine epididymal sperm. Using immunocytochemistry, aquaporins 1, 7 and 11 were detected in fresh and frozen spermatozoa collected from the canine epididymis's head and tail. The aquaporin localisation changed between fresh and frozen spermatozoa and spermatozoa from the epididymis head and tail. Our results showed that AQP1, AQP7 and AQP11 have a specific sperm localisation that the AQP location in head and tail epididymal spermatozoa has a different pattern of immunolocalisation, and cryopreservation produces some changes in the AQP7 and AQP11 localisation. In this way, aquaporins could play an essential role in epidydimal spermatozoa's homeostasis and cryopreservation processes.