Aquaporins 7 and 11 in boar spermatozoa : detection, localisation and relationship with sperm quality

Abstract

Aquaporins (AQPs) are integral membrane water channels that allow transport of water and/or small solutes across cell membranes. Although water permeability is known to play a critical role in mammalian cells, including spermatozoa, little is known about their localisation in boar spermatozoa. Against this background, two different aquaporins, AQP7 and AQP11, were identified in boar spermatozoa by Wwestern blotting and localised through immunocytochemistry analyses. WOur western blot results showed that boar spermatozoa present AQP7 (25KDa) and AQP11 (50KDa). Immunocytochemistry analyses demonstrated that AQP7 is localised at the connecting piece of boar spermatozoa, while AQP11 was found in the head and in the midpiece, and a diffuse labelling was also seen along the tail. Despite differences in AQP7- and AQP11-content being seen between boar ejaculates, these differences were not found to be correlated with sperm quality in the case of AQP7. Conversely, AQP11-content showed a significant correlation (P<0.05) with sperm quality parameters, including sperm membrane integrity and fluidity, and sperm motility. In conclusion, boar spermatozoa present AQP7 and AQP11,. Additionally, and the amounts of the latterAQP11 but not of AQP7 the former are correlated with sperm motility and membrane integrity.