Cold-induced damage in boar sperm cooled to 5°C in Lactose Egg Yolk (LEY) medium with different Glycerol concentrations

• Published in: Animal reproduction science 2024-05, Vol.264, p.107455-107455, Article 107455
• Main Authors: Torres, Pablo, Malcervelli, Daniela Marina, Cartelle, Jonathan Hernán, Fischman, María Laura, Cisale, Humberto Osvaldo
• Format: Article
• Language: English
• Subjects: Animals; Boar; Cold Temperature; Cooling; Cryocapacitation; Cryopreservation - methods; Cryopreservation - veterinary; Cryoprotective Agents - pharmacology; Egg Yolk - chemistry; Glycerol; Glycerol - pharmacology; Lactose - pharmacology; Male; Motility; Semen Preservation - methods; Semen Preservation - veterinary; Sperm Motility - drug effects; Spermatozoa; Spermatozoa - drug effects; Spermatozoa - physiology; Swine
• ISSN: 0378-4320; 1873-2232
• DOI: 10.1016/j.anireprosci.2024.107455

Boar sperm is highly susceptible to cold damage. When temperature drops to 5°C, the plasmatic membrane is destabilized. The freezing process causes a reduction of the fertility window because frozen/thawed boar sperm has less survivability. The aim of this work was to analyze the effect on sperm characteristics and response to capacitation stimuli of cooling to 5°C using a controlled protocol. Also, we evaluated if the addition of Glycerol 2% or 3% at 5°C was able to modify these parameters. For this purpose, we assessed motility, plasmatic membrane integrity and acrosomal membrane status. Capacitation was induced using Tyrode´s capacitating medium (TCM) and assessed by chlortetracycline stain and induction of acrosomal reaction with Progesterone. Motility patterns were analyzed using a CASA system. These tests were performed at three different points of the freezing curve: 37°C; 17°C and 5°C. Response to TCM vs TBM was only significant at 37°C. While at 37°C and 17°C capacitated sperm was below 20%, at 5°C reached 50% both in the TBM and TCM. CASA analysis showed that spermatozoa exposed to TCM had higher LIN and WOB than those in TBM. All parameters were similar in the Glycerol concentrations studied. These results suggest that the chilling process may be causing an effect similar to cryocapacitation along the cooling curve, starting subtle at 17°C and reaching 50% of the sperm population at 5°C, being independent of Glycerol concentration. •Cryocapacitation of boar sperm starts at 17°C and affects 50% of sperm at 5°C.•Sperm exposed to TCM after cooling to 5°C show high linearity and low oscillation.•Glycerol didn´t modify response to capacitation and induced acrosomal reaction.