Evaluation of spermatozoal function—useful tools or just science

Abstract

Contents Conventional microscopic semen analysis does not provide precise information on the fertilizing potential of a male. The traditional basis for semen evaluation is that male fertility is dependent on production of a “proper” concentration/number of motile, morphologically normal spermatozoa in excess to achieve conception. Many independent studies, especially in human medicine, have demonstrated that the absolute number of spermatozoa does not accurately determine fertility, but their functional competence. Many functional tests of spermatozoa are developed over the last decades. Computer‐assisted sperm analysis (CASA) and flow cytometry have become the gold standard for semen assessment in specialized andrology laboratories. Other functional assays, such as gamete interaction tests, provide additional information regarding the real fertilizing potential of sperm cells. From this point of view, such tests are valuable diagnostic tools in fertility disorders and may be helpful to make a decision which method of treatment to use: pharmacological therapy, intrauterine insemination, introduction of classic IVF, ICSI or exclusion from a breeding programme. The most useful gamete interaction tests include induced acrosome reaction, zona pellucida binding assay, oocyte penetration assay and hyaluronan binding assay. In recent years, andrology has entered into a new era of sophisticated OMICS methods. Genomics, epigenomics, transcriptomics and proteomics brought high hopes for rapid progress in clinical diagnostics.

Effects of the cryopreservation process on dog sperm integrity

“…Cryopreservation also decreased the mitochondrial membrane potential of sperm after cooling and freezing/thawing. Such loss of mitochondrial membrane integrity by any means causes mitochondrial pore formation, leading to decreased mitochondrial activity and the liberation of proapoptotic factors into the cytoplasm, which decreases the lifespan of a sperm cell and begins a degradation phase (Niżański et al, 2012;Niżański et al, 2016).…”

“…Changes in the fluidity of the sperm membrane associated with intracellular accumulation of calcium and increases in tyrosine phosphorylation characterize sperm cell capacitation (Niżański et al, 2012;Niżański et al, 2016;Ortega-Ferrusola et al, 2017). The degenerative processes of sperm can be classified as necrosis or apoptosis, whereby in the latter, the cell plays an active role in its own dissolution through ultrastructural and biochemical modifications coordinated by genetic and molecular induction (Câmara and Guerra, 2008).…”

Nanotechnology-based approach for safer enrichment of semen with best spermatozoa

“…These later studies used iron oxide nanoparticle conjugated with annexin V, to target early apoptotic spermatozoa through the externalized phosphatidylserine residues on their surface membrane and lectin, to bind carbohydrates on prematurely acrosome-reacted spermatozoa [22, 29, 31]. Indeed, both apoptosis and acrosome reaction are common defects that characterize non-viable spermatozoa due to increased ROS levels influencing cellular metabolism [32, 33]. The simultaneous targeting of both sperm defects for removal from semen doses would be of great interest in swine farms.…”

In-depth proteomic analysis of boar spermatozoa through shotgun and gel-based methods

“…With regard to spermatozoa, various methods are being used to shed light on every aspect of their structure and functionality. Motility and motion kinematics of spermatozoa are routinely assessed with computerized systems for objective, highly accurate and repeatable evaluations [ 5 – 7 ], while viability parameters such as the integrity of the plasma, acrosome, and mitochondrial membranes are evaluated with vital fluorescent dyes [ 8 , 9 ]. Still, these critical assessments do not always translate into a consistent prediction of semen quality and fertility.…”