Cryopreservation of Semen in Domestic Animals: A Review of Current Challenges, Applications, and Prospective Strategies

Simple Summary Here we present a comprehensive review of the current literature describing mechanisms of damage incurred by cryopreservation, and we highlight several classical and novel strategies to mitigate this damage and increase sperm survival during the cryopreservation process. Cryopreservation is a way to preserve germplasm with applications in agriculture, biotechnology, and conservation of endangered animals. Cryopreservation has been available for over a century, yet, using current methods, only around 50% of spermatozoa retain their viability after cryopreservation. This loss is associated with damage to different sperm components including the plasma membrane, nucleus, mitochondria, proteins, mRNAs, and microRNAs. To mitigate this damage, conventional strategies use chemical additives that include classical cryoprotectants such as glycerol, as well as antioxidants, fatty acids, sugars, amino acids, and membrane stabilizers. However, clearly current protocols do not prevent all damage. This may be due to the imperfect function of antioxidants and the probable conversion of media components to more toxic forms during cryopreservation.

Automated summary

This comprehensive review examines the mechanisms of damage caused by cryopreservation and highlights classical and novel strategies to reduce this damage and improve sperm survival. Cryopreservation is an important method for preserving germplasm in various fields, but the current methods only yield about 50% viable spermatozoa after cryopreservation. Various sperm components, including the plasma membrane, nucleus, mitochondria, proteins, mRNAs, and microRNAs, can be damaged during the process. Conventional strategies using chemical additives have been employed, but they are not completely effective in preventing damage.