Sperm Cell Membranes of Bulls and Bucks Associated with Sperm Fertility and Freezability

TL;DR

This review discusses how bull and buck sperm cell membranes affect fertility and survival after freezing, highlighting their role in reproductive technologies.

Contribution

The paper emphasizes the importance of membrane characteristics like cholesterol–phospholipid ratios and phase transition temperatures as biomarkers for fertility and freezability.

Findings

Sperm membrane integrity and lipid composition influence fertility and cryopreservation outcomes.

Membrane phase transition temperature and cholesterol–phospholipid ratio are key factors in sperm freezability.

Understanding membrane properties can improve semen extenders and reproductive technologies.

Abstract

Changes caused by cryopreservation can damage membrane integrity and reduce sperm viability. A better understanding of sperm membrane characteristics, including factors like the cholesterol–phospholipid ratio and membrane phase transition temperature, can help identify biomarkers for fertility and freezability. This knowledge also supports the design of improved semen extenders, which protect sperm during storage and enhance assisted reproductive technologies (ART) in animals and humans. Studying sperm membranes at the molecular and cellular levels is therefore key for advancing fertility research, improving breeding programs, and supporting the conservation of endangered species.

Consisting of phospholipids, sperm membranes surround the head and tail, playing essential roles in maintaining cellular structural integrity and functions. Their characteristics directly influence sperm fertility and cryopreservation outcomes. This minireview provides a summary of how sperm fertility and freezability are affected by the characteristics of its cell membranes. The primary emphasis is on the molecular and cellular anatomy as well as the physiology of sperm membranes and their attributes associated with fertility determinants or biomarkers for fertility and freezability. It also explores how this knowledge can guide the development of extenders to improve sperm freezability and enhance reproductive technologies in mammals. By providing integrity, fluidity, and selective permeability, the membranes play vitally important roles in sperm motility, which is required for successful fertilization. Cryopreservation, which involves freezing and thawing of sperm for storage or ART, alters the integrity and functionality of the sperm membranes. Sperm freezability, its viability following freezing and thawing, is influenced by several properties of the sperm cell membranes, such as lipid composition, cholesterol content, and structures and functions of the membrane proteins. This review provides concise information about the nature of sperm membranes. It highlights the importance of understanding specific biophysical and biochemical features, including lipid composition, protein distribution, and membrane phase behavior. Particular attention is given to parameters such as the cholesterol–phospholipid ratio and membrane phase transition temperature (Tm). A deeper understanding of these factors can contribute to the identification of reliable fertility biomarkers and the optimization of cryopreservation techniques used in ART and animal breeding programs. Furthermore, this review underscores the need for comprehensive investigations into the molecular and cellular architecture of sperm cells. Such studies are essential for advancing both fundamental and applied aspects of reproductive biology in food-producing animals, endangered species, and humans.

Figures