Changes in sperm function and structure after freezing in domestic cat spermatozoa

Area of Science:

• Veterinary Science
• Reproductive Biology
• Cryobiology

Background:

• Sperm cryopreservation is vital for genetic material storage.
• Cryopreservation can negatively impact sperm viability and function due to cold shock, osmotic, and oxidative stress.
• Assessing cryoinjury in cat spermatozoa is crucial for improving cryopreservation success.

Purpose of the Study:

• To analyze structural and functional changes in domestic cat spermatozoa after freezing and thawing.
• To evaluate the impact of cryopreservation on sperm motility, viability, acrosome integrity, mitochondrial function, and superoxide anion production.

Main Methods:

• Ejaculated semen samples from 60 domestic cats were analyzed before and after freezing.
• Computer-assisted sperm analysis (CASA) was used for progressive motility assessment.
• Flow cytometry evaluated sperm viability, acrosome integrity, mitochondrial function, and superoxide anion (O2-) levels.

Main Results:

• Cryopreservation significantly altered all evaluated sperm parameters (p < 0.05).
• Motility, viability, acrosome integrity, and mitochondrial function decreased from approximately 80% in fresh samples to 40% in frozen/thawed samples (p < 0.05).
• Superoxide anion (O2-) positive sperm increased significantly post-thawing (p < 0.05).

Conclusions:

• Cryopreservation-induced damage in cat spermatozoa is linked to oxidative stress, evidenced by increased superoxide anion synthesis.
• The observed increase in superoxide anion and loss of functional competence suggest significant cryoinjury.
• Evaluating these specific sperm parameters can enhance the assessment of fresh and frozen semen for assisted reproductive technologies (ART).