Paulina K. Rybnik-Trzaskowska

Bio: Paulina K. Rybnik-Trzaskowska is an academic researcher from Warsaw University of Life Sciences. The author has contributed to research in topics: Sperm & Semen analysis. The author has an hindex of 2, co-authored 2 publications receiving 35 citations.

The Semen pH Affects Sperm Motility and Capacitation.

Abstract: As the chemical environment of semen can have a profound effect on sperm quality, we examined the effect of pH on the motility, viability and capacitation of human sperm. The sperm in this study was collected from healthy males to avoid interference from other factors. The spermatozoa cultured in sperm nutrition solution at pH 5.2, 6.2, 7.2 and 8.2 were analyzed for sperm total motility, progressive motility (PR), hypo-osmotic swelling (HOS) rate, and sperm penetration. Our results showed that these parameters were similar in pH 7.2 and 8.2 sperm nutrition solutions, but decreased in pH 5.2 and 6.2 solutions. The HOS rate exhibited positive correlation with the sperm total motility and PR. In addition, the sperm Na+/K+-ATPase activity at different pHs was measured, and the enzyme activity was significantly lower in pH 5.2 and 6.2 media, comparing with that in pH 8.2 and pH 7.2 solutions. Using flow cytometry (FCM) and laser confocal scanning microscopy (LCSM) analysis, the intracellular Ca2+ concentrations of sperm cultured in sperm capacitation solution at pH 5.2, 6.2, 7.2 and 8.2 were determined. Compared with that at pH 7.2, the mean fluorescence intensity of sperm in pH 5.2 and 6.2 media decreased significantly, while that of pH 8.2 group showed no difference. Our results suggested that the declined Na+/K+-ATPase activity at acidic pHs result in decreased sperm movement and capacitation, which could be one of the mechanisms of male infertility.

Predominance of sperm motion in corners.

Abstract: Sperm migration through the female tract is crucial to fertilization, but the role of the complex and confined structure of the fallopian tube in sperm guidance remains unknown. Here, by confocal imaging microchannels head-on, we distinguish corner- vs. wall- vs. bulk-swimming bull sperm in confined geometries. Corner-swimming dominates with local areal concentrations as high as 200-fold that of the bulk. The relative degree of corner-swimming is strongest in small channels, decreases with increasing channel size, and plateaus for channels above 200 μm. Corner-swimming remains predominant across the physiologically-relevant range of viscosity and pH. Together, boundary-following sperm account for over 95% of the sperm distribution in small rectangular channels, which is similar to the percentage of wall swimmers in circular channels of similar size. We also demonstrate that wall-swimming sperm travel closer to walls in smaller channels (~100 μm), where the opposite wall is within the hydrodynamic interaction length-scale. The corner accumulation effect is more than the superposition of the influence of two walls, and over 5-fold stronger than that of a single wall. These findings suggest that folds and corners are dominant in sperm migration in the narrow (sub-mm) lumen of the fallopian tube and microchannel-based sperm selection devices.

Insights into pH regulatory mechanisms in mediating spermatozoa functions.

Abstract: Regulation of pH in spermatozoa is a complex and dynamic process as sperm cells encounter different pH gradients during their journey from testes to the site of fertilization in female genital tract. The precise regulations of pH in sperm cells regulate the sperm functions such as motility, hyperactivity, capacitation, and acrosome reaction. Electrophysiological, pharmacological, and molecular studies have revealed the presence of different ion channels and exchanger systems which regulate intracellular pH in sperm cells as well as regulate sperm functions. Recent studies also have shown the potential involvement of pH in the regulation of fertility competence of sperm cells, and alterations in pH have shown to impede sperm functions. This mini-review discusses the probable mechanisms involved in pH regulation in sperm cells and how pH is involved in regulation of various sperm functions.