The aim of this study was to investigate the relationship between apoptotic markers present in human spermatozoa, namely phosphatidylserine translocation (PST) from the inner to the outer layer of the cytomembrane and the active form of caspase-3 (c3) versus the fertilizing potential of male gametes in conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) models. A total of 116 male patients treated with their partners for infertility underwent basic semen analysis and an assessment of the presence of PST and the active c3 in sperm using flow cytometry. Forty patients underwent IVF, group A, while 76 patients underwent ICSI, group B. The fertilizing potential of the gametes was measured as the percentage of oocytes with pronuclei present after either procedure. PST and active c3 were identified in vital gametes, mainly in the midpiece area. Concentration, motility, morphology, and viability of spermatozoa strongly negatively correlated with both markers. In group A, a negative correlation between both markers and the success rate of conventional IVF was observed (r = −0.4, p = 0.04 for PST; r = −0.4, p = 0.02 for active c3, respectively). In group B, the success rate of ICSI did not correlate with either marker (r = −0.2, p = 0.85 for PST and r = 0.1, p = 0.51 for active c3). The two apoptotic markers localized in the sperm midpiece area may affect their function not only by decreasing basic andrologic parameters but also by reducing the probability of conception. Therefore, analysis of PST and active c3 in the sperm of patients undergoing infertility treatment should be recommended.

BackgroundIt is assumed that spermatozoa are target cells for estrogens however, the mechanism of their action is not fully understood. The aim of this study was to investigate the influence of 17β-estradiol (E2) on the human spermatozoa mitochondrial function.MethodsThe effects on spermatozoa of E2 at final concentrations of 10−10, 10−8 and 10−6 M were studied regarding the following phenomena: (1) kinetics of intracellular free calcium ions changes (using Fluo-3), (2) mitochondrial membrane potential ΔΨm (using JC-1 fluorochrome), (3) production of superoxide anion in mitochondria (using MitoSOX RED dye), (4) spermatozoa vitality (propidium iodide staining) and (5) phosphatidylserine membrane translocation (staining with annexin V marked with fluorescein).ResultsE2 initiated rapid (within a few seconds) dose dependent increase of intracellular free calcium ions concentration. E2 was changing the mitochondrial membrane potential: 10−8 M initiated significant increase of percentage of high ΔΨm spermatozoa while the 10−6 M induced significant decrease of high ΔΨm cells. In spermatozoa stimulated with E2 10−6 M a significant increase of mitochondrial superoxide anion level was observed. 2 h incubation of spermatozoa with E2 did not alter cells vitality nor stimulated phosphatidylserine membrane translocation, for all three doses.Conclusions17β-estradiol affected the human spermatozoa mitochondrial function. E2 in low concentration improved while in high concentration might deteriorate mitochondrial function.

The complex structure of the human spermatozoa membrane comprises five topographic domains. Transmembrane asymmetry of the distribution of phospholipids including phosphatidylserine (PS) is considered a marker of cell activity. The objective of the study was to determine which cytomembrane domains of human spermatozoa are involved in PS membrane translocation and to identify the possible relationship of PS translocation with spermatozoa morphology and vitality. In normozoospermic semen of 35 donors, annexin-V labeling with fluorescein determined PS translocation. Propidium iodide staining distinguished between vital and dead spermatozoa. Three types of PS membrane translocation have been distinguished: (1) in the midpiece, (2) in the acrosomal part and (3) simultaneously in the midpiece and acrosomal part. In morphologically normal vital spermatozoa, PS translocation occurred in the midpiece but never in the equatorial region. In dead spermatozoa, simultaneous PS translocation in the midpiece and acrosomal part was most often observed. The difference between proportions of, respectively, vital and dead spermatozoa presenting PS translocation located in different domains was significant (P < 0.0001). In vital cells, there was no difference in PS translocation prevalence between morphologically normal and abnormal spermatozoa (P > 0.05). The strict relation of PS translocation to specific membrane domains indicates functional specificity. It seems doubtful to include this phenomenon in physiological mechanisms of elimination of abnormal spermatozoa.

Objectives: The aim of the study was to investigate the influence of 17β-estradiol (main endogenous estrogen) and selected xenoestrogens (genistein, bisphenol-A), individually and in combination, on the mitochondrial function of human spermatozoa. In natural environment, human beings are exposed to multiple xenoestrogens, so their impact is combined with endogenous steroids. Material and methods:The effects of ligands on human spermatozoa were assessed regarding the following phenomena: spermatozoa vitality (propidium iodide staining), phosphatidylserine membrane translocation (staining with annexin V marked with fluorescein), mitochondrial membrane potential (using JC-1 fluorochrome), and production of superoxide anion in mitochondria (using MitoSOX RED dye).Results: Two-hour incubation of spermatozoa with 17β-estradiol , genistein, and bisphenol-A neither altered cell vitality nor stimulated phosphatidylserine membrane translocation. Incubation of spermatozoa with 17β-estradiol or bisphenol-A separately, as well as incubation with the three ligands simultaneously, resulted in altered mitochondrial membrane potential. Spermatozoa incubation with the three ligands significantly increased the mitochondrial superoxide anion level. Conclusions:It seems safe to conclude that human spermatozoa mitochondria are target cell structures for both, 17β-estradiol and xenoestrogens. The reaction to the 17β-estradiol and xenoestrogens mixture suggests a synergistic mechanism of action. Xenoestrogens may increase the sensitivity of spermatozoa to 17β-estradiol.

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