The importance and characteristics of sperm diluents

Abstract

Despite the significant progress in sperm cryopreservation methods in recent years, research has proven that long-term storage of sperm in freezing and cold storage causes serious damage to sperm. The occurrence of fat peroxidation and the metabolism of spermatozoids results in destruction of spermatozoa during freezing and storage. Temperature shock, the formation of intracellular ice crystals, cellular dehydration, increased salt concentration and osmotic shock may occur during the freezing and thawing process. In addition, cryopreservation causes harmful structural changes in the plasma membrane. Changes in membrane permeability to some ions such as calcium during the freezing and thawing process have been reported. Also, during cryopreservation, the formation of intracellular and extracellular ice causes cell destruction and death. The sperm plasma membrane is the main site of damage during the freezing and thawing process and is very sensitive to lipid peroxidation due to the presence of many unsaturated fatty acids. These changes may have a role in the accumulation of toxic products of metabolism, mainly reactive oxygen species (ROS) that are generated through lipid peroxidation of sperm membranes. Small amounts of ROS play an important role in sperm capacitation, increased sperm motility, acrosome reaction, and oocyte fertilization in humans, cows, horses, pigs, and rams. Therefore, to solve these problems, various antioxidants, preservatives and chelators are used in sperm extenders.

Keywords

• additives
• cooled preservation
• cryopreservation
• seminal plasma
• sperm.