Structure, function, and localization of aquaporins: their possible implications on gamete cryopreservation

The discovery of water channels (aquaporins, AQPs) was a landmark event for the clarification of water transport through the plasma membrane. AQPs belong to a family of intrinsic membrane proteins that act as selective channels for water and for solutes such as glycerol and urea. AQPs were found in different tissues and organs, including male and female reproductive systems. In the swine female reproductive system, the AQPs were localized in the uterus, oviduct, and ovary, as well as in the granulosa cells from primordial follicles. Knowing the involvement of AQPs with the male and female germ cells, as well as their acknowledged role in transporting water through the plasma membrane, the research of these proteins in cryopreservation processes becomes essential. Thus, this review aims to describe the structure and function of AQPs in membranes, highlighting their role in the reproductive system (male and female). We also discuss the involvement of AQPs in cryopreservation, focusing on the effect and importance of these proteins on the rates of vitrification protocols for preantral follicles present in the ovarian tissue of domestic mammals.