Recent Advances in Cryopreservation of Animal Genetic Resources: Principles, Influencing Factors, and Material-Specific Challenges.

Cryopreservation plays a critical role in the long-term preservation of biological materials and has become an indispensable technology in biomedicine, agriculture, animal breeding, and biodiversity conservation. Despite substantial advances in cryobiology, the preservation of cells and tissues at ultra-low temperatures remains limited by cryoinjuries associated with ice crystal formation, osmotic stress, oxidative damage, and cellular dehydration. This review provides an overview of the historical development and fundamental principles of cryopreservation and critically summarizes the key factors affecting cryopreservation efficiency, including cryoprotective agents, antioxidants, osmotic balance, freezing and thawing protocols, and emerging ice-controlling materials. In addition, recent advances in the cryopreservation of diverse biological materials-such as sperm, oocytes, embryos, stem cells, and gonadal tissues from different animal species-are critically discussed, with particular attention to species-specific differences and the distinction between post-thaw survival and functional recovery. Finally, the current limitations of existing cryopreservation technologies and future research directions are highlighted to facilitate the development of safer and more effective preservation strategies for animal genetic resource conservation and biomedical applications.