Eva Tvrdá

Impact of oxidative stress on male fertility - a review.

Oxidative stress is a state related to increased cellular damage caused by oxygen and oxygen-derived free radicals known as reactive oxygen species (ROS). It is a serious condition, as ROS and their metabolites attack DNA, lipids and proteins, alter enzymatic systems and cell signalling pathways, producing irreparable alterations, cell death and necrosis. While small amounts of ROS have been shown to be required for several functions of spermatozoa, their excessive levels can negatively impact the quality of spermatozoa and impair their overall fertilising capacity. These questions have recently attracted the attention of the scientific community; however, research aimed at exploring the role of oxidative stress and antioxidants associated with male fertility is still at its initial stages. This review summarises the current facts available in this field and intends to stimulate interest in basic and clinical research, especially in the development of effective methods for the diagnosis and therapy of semen damage caused by oxidative stress.

The impact of lead and cadmium on selected motility, prooxidant and antioxidant parameters of bovine seminal plasma and spermatozoa

The aim of this study was to investigate the effects of lead (Pb) and cadmium (Cd) content on basic motility characteristics (motility-MOT, progressive motility-PROG) as well as selected markers of the prooxidant-antioxidant balance (catalase-CAT, glutathione-GSH, malondialdehyde-MDA) in bovine seminal plasma and spermatozoa. Twenty five semen samples were collected from breeding bulls and used in the study. Motility analysis was carried out using the Computer Assisted Sperm Analysis (CASA) system. The samples were centrifuged, fractions of seminal plasma and spermatozoa were separated, lysates were prepared from the sperm cell fractions. Pb and Cd concentrations were determined by the voltametric method (ASV), antioxidants and MDA were analyzed by UV/Vis spectrophotometry. The analysis showed that the average concentration of Pb in the seminal plasma was 0.23 ± 0.02 μg/mL, while its amount in the sperm cells was significantly higher (0.41 ± 0.07 μg/mL; P < 0.05). The average Cd content in bovine seminal fractions was similar and non-significant: 0.09 ± 0.01 μg/mL in the seminal plasma and 0.11 ± 0.01 μg/mL in spermatozoa (P > 0.05). The correlation analysis revealed that both heavy metals were significantly negatively correlated with MOT and PROG (P < 0.05; P < 0.01; P < 0.001), CAT (P < 0.05; P < 0.01) as well as GSH (P < 0.05; P < 0.01) but significantly positively associated with MDA as the marker of lipid peroxidation (P < 0.05; P < 0.01). Moreover the samples were categorized in three quality groups (Excellent, Good, Moderate) according to their motility values. The lowest Pb, Cd and MDA concentrations but the best antioxidant characteristics were found in samples of the best quality, moderate quality samples exhibited the highest Pb, Cd and MDA content together with the worst antioxidant capacity. This study demonstrates that Pb and Cd are serious toxic elements, which are able to increase the risk of seminal oxidative stress development and a subsequent decrease of male fertility.

Bibliometrics: tracking research impact by selecting the appropriate metrics

Traditionally, the success of a researcher is assessed by the number of publications he or she publishes in peer-reviewed, indexed, high impact journals. This essential yardstick, often referred to as the impact of a specific researcher, is assessed through the use of various metrics. While researchers may be acquainted with such matrices, many do not know how to use them to enhance their careers. In addition to these metrics, a number of other factors should be taken into consideration to objectively evaluate a scientist′s profile as a researcher and academician. Moreover, each metric has its own limitations that need to be considered when selecting an appropriate metric for evaluation. This paper provides a broad overview of the wide array of metrics currently in use in academia and research. Popular metrics are discussed and defined, including traditional metrics and article-level metrics, some of which are applied to researchers for a greater understanding of a particular concept, including varicocele that is the thematic area of this Special Issue of Asian Journal of Andrology. We recommend the combined use of quantitative and qualitative evaluation using judiciously selected metrics for a more objective assessment of scholarly output and research impact.

Dose- and time-dependent effect of copper ions on the viability of bull spermatozoa in different media

The purpose of this in vitro study was to determine the effect of copper (Cu) on the motility and viability of spermatozoa in the presence of different culture media. Specifically, we examined the dose- and time-dependent effect of copper ions (Cu2+) on the motility and viability of spermatozoa during different time periods (Time 0 h, 1 h, 24 h). The percentage of motile spermatozoa and progressive motile spermatozoa was determined after exposure to concentrations of 3.9; 7.8; 15.6; 31.2; 62.5; 125; 250; 500; 1000 μM/L of Cu2+ using the Sperm VisionTM CASA (Computer Assisted Semen Analyzer) system. The cell viability was measured by the MTT (metabolic activity) assay. The initial spermatozoa motility in the presence of Cu2+ in physiological saline solution (PS) showed slight increased values at doses <31.20 μM/L of Cu2+ compared to the control group. The long-term cultivation (Time 24 h) reduced the average motility values in all experimental groups (P < 0.001) in comparison to the control group. Identical spermatozoa motility was detected for the percentage of progressive motile spermatozoa during all time periods. The culture medium containing 20 % bovine serum albumin (BSA), triladyl and 5 % glucose increased the overall percentage of spermatozoa motility after 1 h of cultivation. A concurrently maintained motility of spermatozoa at doses <62.50 μM/L of Cu2+ during the long-term in vitro cultivation confirms the protective effect of albumin. The cell viability was decreased significantly (P < 0.001) in all experimental groups with copper administration. The obtained data point out that Cu2+ at high doses is a toxic element on the spermatozoa motility, which subsequently disrupts the viability of cells. However, using a suitable culture medium containing an energy component- and protein-rich substrate, the spermatozoa motility could increase.

Male Reproductive Cancers and Infertility: A Mutual Relationship

Reproductive dysfunction and malignancies related to the male gender represent a serious health concern, whose incidence has significantly risen over the past years. Prior to treatment, testicular or prostate cancer patients often display poor semen characteristics similar to subfertile or infertile patients. This fact is underscored by cases where the malignancy is often diagnosed in males who undergo a general fertility screening. This review aims to examine the associations between male infertility and reproductive cancers focusing on common etiologies and biological mechanisms underlining these pathologies. Furthermore, we discuss compelling epidemiological data hypothesizing that male reproductive failure may act as a precursor of future andrological malignancies, including testicular or prostate cancer, thus providing a stimulus for a more specific research in male reproductive health and emphasizing the importance of this relation for physicians taking care of male patients with a reproductive disease.

The effect of nonylphenol on the motility and viability of bovine spermatozoa in vitro

The objective of this in vitro study was to determine the effect of nonylphenol (NP) as an environmental toxicant on the spermatozoa motility and viability. The dose- and time-dependent effect of nonylphenol (1, 10, 100 and 200 μg/mL) dissolved either in 0.1% dimethyl sulfoxide (DMSO) or 0.1% ethanol (ETOH) on the motility and viability of bovine spermatozoa, as a cell model, during several time periods (0 h, 2 h, 4 h and 6 h) were examined. The motility of spermatozoa was determined by the Sperm VisionTM CASA (Computer Assisted Semen Analyzer) system. The results showed decreased spermatozoa motility in all experimental groups with the addition of NP dissolved in 0.1% DMSO and 0.1% ETOH (P < 0.001 and P < 0.05). The lowest spermatozoa motility was found at doses > 100 μg/mL of NP in comparison with the control group. The viability of bovine spermatozoa detected by the MTT cytotoxicity assay was decreased significantly (P < 0.001) in all experimental groups with NP dissolved in 0.1% ETOH. The viability in groups with NP dissolved in 0.1% DMSO was significantly (P < 0.05) decreased at 1 μg/mL of NP and significantly decreased (P < 0.001) at doses > 10 μg/mL of NP. After 6 h of culture the MTT assay proved a negative effect of all NP doses the on cell viability. The obtained data clearly indicate the negative effect of NP as an endocrine disruptor on spermatozoa motility and viability, which should be seriously considered in the case of exposure to NP in animals and humans and as a reason of male reproductive dysfunction.

Effects of mercury on the steroidogenesis of human adrenocarcinoma (NCI-H295R) cell line

In this study the NCI-H295R human adrenocortical carcinoma cell line was used as an in vitro biological model to study the effect of mercury (HgCl2) on the steroidogenesis. The cells were cultured for 48 h with addition of 1.0; 5.0; 25; 50 or 100 μM of HgCl2 and compared to control. Cell viability was measured by the MTT (metabolic activity) assay estimation for the mitochondria structural integrity. Quantification of testosterone and progesterone directly from aliquots of the medium was performed by enzyme linked immunosorbent assay (ELISA). Concentration-dependent depression in testosterone production was detected particularly for higher concentration of Hg2+. Progesterone production was also decreased, but at the lower concentrations (1.0 and 5.0 μM) of Hg2+ this decline was lower compared to depression of testosterone. The cell viability significantly decreased at 25 μM and higher concentration of Hg2+. However, at 25 μM Hg2+ exposure the cell viability remained relatively high (> 80%). Results of the study indicate dose-dependent decreases in both testosterone and progesterone production of H295R cell culture following a 48 h in vitro HgCl2 exposure. The results suggest that Hg has detrimental effects on steroid hormone synthesis also at very low concentrations and consecutively on reproductive physiology.

Selected heavy metals versus antioxidant parameters in bull seminal plasma – A comparative study

To investigate the effects of lead (Pb) and cadmium (Cd) content on basic motility characteristics (motility, progressive motility) and selected antioxidant parameters (total antioxidant status - TAS, superoxide dismutase - SOD, albumin - ALB) in the bovine seminal plasma semen samples were collected from breeding bulls and used in the study. Motility analysis was carried out using the Computer Assisted Sperm Analysis (CASA) system. Subsequently, the samples were centrifuged and fractions of seminal plasma were collected. Pb and Cd concentrations were determined by the voltametric method (ASV), antioxidant parameters were analyzed by UV/VIS spectrophotometry using commercial kits. The analysis showed that the average concentrations of the trace elements were 0.57 ± 0.01μg/mL for Pb and 0.11±0.01 μg/mL for Cd. The correlation analysis revealed that both heavy metals were negatively correlated with motility (r = −0.777; P < 0.001 for Pb and r = −0.786; P < 0.001 for Cd), progressive motility (r = −0.763; P < 0.001 for Pb and r = −0.792; P < 0.001 for Cd), TAS (r = −0.375; p > 0.05 and r = −0.334; P > 0.05, respectively), SOD (r = −0.746; P < 0.001 and r = −0.537; P < 0.05, respectively) as well as with ALB (r = −0.609; P < 0.01 and r = −0.699; P < 0.001, respectively). Moreover the samples were categorized in three quality groups (Excellent, Good, Medium) according to their motility values. The lowest Pb and Cd concentrations but the best antioxidant characteristics were found in samples of excellent quality, medium quality samples were described by the highest Pb and Cd concentration and the worst antioxidant power. This study demonstrates that Pb and Cd are serious toxic elements, which are able to increase the risk of oxidative stress development and a subsequent decrease of semen quality.

Curcumin has protective and antioxidant properties on bull spermatozoa subjected to induced oxidative stress

Over the past decades, there has been an emphasis on assessment of the use of natural compounds in the prevention or repair of oxidative injury to spermatozoa. Curcumin (CUR) is a natural phenol with powerful antioxidant properties. The aim of the present study was to examine if CUR could reverse reactive oxygen species (ROS)-mediated alterations to the motility, viability and intracellular antioxidant profile of bull spermatozoa subjected to a prooxidant (i.e., ferrous ascorbate - FeAA). Spermatozoa were washed from recently collected semen samples, suspended in 2.9% sodium citrate and subjected to CUR treatment (5, 10, 25 and 50μmol/L) in the presence or absence of FeAA (150μmol/L FeSO4 and 750μmol/L ascorbic acid) during a 6h in vitro culture. Spermatozoa motility characteristics were assessed using the SpermVision computer-aided spermatozoa analysis (CASA) system. Cell viability was examined with the metabolic activity (MTT) assay, ROS generation was quantified using luminometry and the nitroblue-tetrazolium (NBT) test was used to quantify the intracellular superoxide formation. Cell lysates were prepared at the end of the culture to assess the intracellular activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) as well as the concentrations of glutathione (GSH) and malondialdehyde (MDA). Treatment with FeAA led to a reduced spermatozoa motility (P<0.001), viability (P<0.001) and decreased the antioxidant characteristics of the samples (P<0.001) but increased the ROS generation (P<0.001), superoxide production (P<0.001) and lipid peroxidation (P<0.001). The CUR treatment led to a preservation of spermatozoa motion (P<0.001), mitochondrial activity (P<0.001) and antioxidant characteristics (P<0.05 with SOD and GSH; P<0.01 with CAT and GPx), revealing the concentration range of 25-50μmol/L CUR to be the most effective for sustaining spermatozoa viability. Data from the present study suggest that CUR exhibits significant protective and ROS-scavenging characteristics which may prevent oxidative insults to spermatozoa and thus preserve the functional activity of male gametes.

Free radical and superoxide reactivity detection in semen quality assessment: past, present, and future

Oxidative stress is a well-established cause of male infertility, with reactive oxygen species (ROS) impairing sperm production, motility, membrane, and DNA integrity. Currently, most clinics do not test infertile patients for the imbalance between ROS generation and the ability of the antioxidants to scavenge them, although there is a clear need for andrology laboratories to be able to identify and/or quantify seminal oxidative stress. As such there is a clinical urgency for an inexpensive and easy-to-perform assay able to identify oxidative stress in semen. The aim of this review is to provide information on the currently available methods to assess and quantify ROS and particularly superoxide in male reproductive cells, tissues, and fluids which may have a significant clinical utility in identifying men with impaired fertility associated with oxidative stress. Through a deeper understanding of oxidative stress and its assessment options, clinical andrology labs may better assist patients to achieve increased rates of fertility and pregnancy.