Markers for Sperm Freezability and Relevance of Transcriptome Studies in Semen Cryopreservation: A Review

Abstract

Advances in sperm assessment techniques have ofered new perspectives to improve the technology of semen cryopreservation. This review addresses some recent achievements in the proteomics of seminal plasma and spermatozoa and exempliies its importance as markers for sperm fertility following cryopreservation. Recent advances in transcriptome studies on sperm RNA-Seq data have generated new information aimed to unravel the physiological roles of RNAs in the sperm-egg fertilization processes and their associations with male fertility. The relevance of the sperm freezability markers and the potential associations of RNA-proiling sequences with the sperm biological functions have been discussed.

Exploration of miRNA and mRNA Profiles in Fresh and Frozen-Thawed Boar Sperm by Transcriptome and Small RNA Sequencing

“…Cryopreservation has been reported to affect sperm motility and viability and increase ROS-induced oxidative stress, DNA fragmentation, and apoptosis [ 13 , 43 , 44 ]. Cryopreservation has also been linked to calcium homoeostasis, acrosome integrity, structural and functional alterations in sperm plasma membranes, which could result in leakage of essential intracellular enzymes such as antioxidants, acrosin, aspartate aminotransferase (AspAT), or energy substrates (i.e., adenosine triphosphate (ATP)), and ultimately lead to cell death [ 2 , 45 ]. The integrity of sperm DNA is of vital importance to sperm cells [ 13 ].…”

“…The sperm mitochondrial membrane potential is essential for ATP production, which undoubtedly plays a central role in supporting the energy requirement for several biological functions. Many past studies have demonstrated that cryo-induced damage to the mitochondrial membrane potential of sperm is one the leading causes of their declined fertilizing capability [ 45 ].…”

Improvement of Post-Thaw Sperm Kinematics and DNA Integrity of Cross-Bred Bovine Sperm by Incorporating DGC as Selection Method Prior to Cryopreservation

“…In conclusion, the outcomes of the kinetic parameters for post-thaw cryopreserved spermatozoa show that the values improved with DGC separation system and have increased the occurrence of sperm with intact DNA by reducing the values obtained from DFI analysis. This further validates that spermatozoa from the CDGC group sustained minimal damage to their DNA following separation and cryopreservation and is suitable for implementation in various artificial insemination procedures (Joint FAO, 2005;Fraser, 2017;Parthipan et al, 2017). By having sperm with high DNA integrity, the sperm conserved its repair mechanism and was able to reduce the detrimental effects of cryodamage.…”

Sperm Transcriptome Analysis Accurately Reveals Male Fertility Potential in Livestock

“…The evaluation of semen quality has begun to involve parameters for examining sperm DNA fragmentation. Researchers have reported various DNA fragmentation assay methods, ranging from chromomycin A3 staining [ 9 , 10 ], Hoechst, sperm Halomax kit [ 11 , 12 , 13 , 14 , 15 ], acridine orange [ 16 ], TUNEL assay [ 17 , 18 , 19 ], and SCSA [ 4 , 11 , 20 ]. This evaluation aims to investigate the competence of sperm to fertilize oocytes in the female reproductive tract.…”

“…Transcriptomic analysis was carried out by investigating the function of the transcriptome product (transcriptome) of sperm in the form of RNA consisting of coding RNA and non-coding RNA. Transcriptomic studies can reveal the biological function of the sperm transcriptome [ 14 ]. RNA coding is limited to messenger RNA, while non-coding RNA consists of several types, such as long non-coding RNA (lncRNA), ribosomal RNA (rRNA), transfer RNA (tRNA), t-RNA-derived small RNA (tsRNA), circular RNA (circRNA), and others.…”