Effect of a pre-freezing treatment with cholesterol-loaded cyclodextrins on boar sperm longevity, capacitation dynamics, ability to adhere to porcine oviductal epithelial cells in vitro and DNA fragmentation dynamics

The aim of this work was to examine how a pre-freezing treatment with cholesterol-loaded cyclodextrins (CLC) affects boar sperm longevity, capacitation dynamics, ability to bind to a porcine telomerase-immortalised oviductal epithelial cell line (TERT-OPEC) in vitro and DNA integrity dynamics after freeze-thawing. Although the samples treated with CLC exhibited lower sperm quality than the control samples (P < 0.05) immediately after thawing, these differences disappeared (P > 0.05) after long-term incubation (26 h at 37 or 16 degrees C). Additionally, the CLC-treated spermatozoa underwent similar capacitation and DNA fragmentation dynamics as the control spermatozoa (P > 0.05). However, CLC-treated spermatozoa were better able to bind to TERT-OPEC in vitro (P < 0.0001). In conclusion, the pre-freezing treatment of boar spermatozoa with CLC enhanced the ability of the spermatozoa to bind to TERT-OPEC in vitro, which could have an effect on the establishment of the sperm reservoir in the ampullary-isthmic junction in vivo. Additionally, frozen-thawed spermatozoa can be stored at 16 degrees C for at least 6 h without a significant observable decline in sperm quality, which could be beneficial for the transport of thawed diluted doses of spermatozoa from the laboratory to the farm.