Antioxidants: Characterization, natural sources, extraction and analysis

Background Mitochondria are multitasking organelles involved in ATP synthesis, reactive oxygen species (ROS) production, calcium signalling and apoptosis; and mitochondrial defects are known to cause physiological dysfunction, including infertility. The goal of this review was to identify and discuss common themes in mitochondrial function related to mammalian reproduction. Methods The scientific literature was searched for studies reporting on the several aspects of mitochondrial activity in mammalian testis, sperm, oocytes, early embryos and embryonic stem cells. Results ATP synthesis and ROS production are the most discussed aspects of mitochondrial function. Metabolic shifts from mitochondria-produced ATP to glycolysis occur at several stages, notably during gametogenesis and early embryo development, either reflecting developmental switches or substrate availability. The exact role of sperm mitochondria is especially controversial. Mitochondria-generated ROS function in signalling but are mostly described when produced under pathological conditions. Mitochondria-based calcium signalling is primarily important in embryo activation and embryonic stem cell differentiation. Besides pathologically triggered apoptosis, mitochondria participate in apoptotic events related to the regulation of spermatogonial cell number, as well as gamete, embryo and embryonic stem cell quality. Interestingly, data from knock-out (KO) mice is not always straightforward in terms of expected phenotypes. Finally, recent data suggests that mitochondrial activity can modulate embryonic stem cell pluripotency as well as differentiation into distinct cellular fates. Conclusions Mitochondria-based events regulate different aspects of reproductive function, but these are not uniform throughout the several systems reviewed. Low mitochondrial activity seems a feature of 'stemness', being described in spermatogonia, early embryo, inner cell mass cells and embryonic stem cells.

/pdf/mitochondrial-functionality-in-reproduction-from-gonads-and-3sa7b019k2.pdf

Mitochondrial functionality in reproduction: from gonads and gametes to embryos and embryonic stem cells

Computer-assisted sperm analysis (CASA): capabilities and potential developments.

Cryoprotectants: A review of the actions and applications of cryoprotective solutes that modulate cell recovery from ultra-low temperatures.

Sperm cryopreservation update: Cryodamage, markers, and factors affecting the sperm freezability in pigs.

Effect of epididymis handling conditions on the quality of ram spermatozoa recovered post-mortem.

We have applied a statistical protocol based on principal component analysis, clustering methods, and discriminant analysis for the identification of sperm subpopulations in computer-assisted sperm analysis (CASA) data. Samples were obtained from the cauda epididymis of 11 Iberian red deer and cryopreserved following a standard protocol. Motility by CASA was analyzed just after sperm recovery, just before freezing, and after thawing, and eight motility descriptors for each individual spermatozoon were recorded. Sperm viability and acrosomal status were also assessed. Subpopulation analysis was performed in four sequential steps: principal component analysis using the eight motility descriptors; nonhierarchical clustering analysis (k-means) using the first two principal components; hierarchical clustering analysis (UPGMA); and selection of the final number of clusters. Three clusters were obtained for each motility analysis: slow and nonlinear; rapid and linear; and rapid, high ALH, nonlinear. We detected variations in the clusters between treatments (initial, prefreezing and postthawed). Indeed, motility increased and linearity decreased in the prefreezing analysis. A discriminant analysis isolated three descriptors that were used again in the same statistical analysis, giving four clusters that resembled the pattern found in the first classification. We also performed a clustering analysis of the males according to prefreezing/postthawed variation of total motility, viability, and acrosomal status. The proportion of the linear subpopulations in the prefreezing treatment, in both clustering analyses, correlated positively with postthawed viability recovery. Our results show that clustering analysis of CASA data gives useful and practical information that is not obtained by conventional sperm analysis.

https://bioone.org/journals/biology-of-reproduction/volume-72/issue-2/biolreprod.104.032730/Sperm-Subpopulations-in-Iberian-Red-Deer-Epididymal-Sperm-and-Their/10.1095/biolreprod.104.032730.pdf

Sperm subpopulations in Iberian red deer epididymal sperm and their changes through the cryopreservation process.

https://digital.csic.es/bitstream/10261/143987/1/subpopulation.pdf

Paulino de Paz

Papers

Effect of epididymis handling conditions on the quality of ram spermatozoa recovered post-mortem.

Sperm subpopulations in Iberian red deer epididymal sperm and their changes through the cryopreservation process.

Statistical Series: Opportunities and challenges of sperm motility subpopulation analysis.

Use of chromatin stability assay, mitochondrial stain JC-1, and fluorometric assessment of plasma membrane to evaluate frozen-thawed ram semen

Comparison of two methods for obtaining spermatozoa from the cauda epididymis of Iberian red deer