In vitro effect of 4-nonylphenol on human chorionic gonadotropin (hCG) stimulated hormone secretion, cell viability and reactive oxygen species generation in mice Leydig cells

Nonylphenol is considered an endocrine disruptor and has been reported to affect male reproductive functions. In our in vitro study, we evaluated the effects of 4-nonylphenol (4-NP) on cholesterol levels, hormone formation and viability in cultured Leydig cells from adult ICR male mice. We also determined the potential impact of 4-NP on generation of reactive oxygen species (ROS) after 44 h of cultivation. The cells were cultured with addition of 0.04; 0.2; 1.0; 2.5 and 5.0 μg/mL of 4-NP in the present of 1 IU/mL human chorionic gonadotropin (hCG) and compared to the control. The quantity of cholesterol was determined from culture medium using photometry. Determination of hormone production was performed by enzyme-linked immunosorbent assay. Metabolic activity assay was used for quantification of cell viability. The chemiluminescence technique, which uses a luminometer to measure reactive oxygen species, was employed. Applied doses of 4-NP (0.04-5.0 μg/mL) slight increase cholesterol levels and decrease production of dehydroepiandrosterone after 44 h of cultivation, but not significantly. Incubation of 4-NP treated cells with hCG significantly (P < 0.001) inhibited androstenedione, but not testosterone, formation at the highest concentration (5.0 μg/mL). The viability was significantly (P < 0.05); (P < 0.001) increased at 1.0; 2.5 and 5.0 μg/mL of 4-NP after 44 h treatment. Furthermore, 44 h treatment of 4-NP (0.04-5.0 μg/mL) caused significant (P < 0.001) intracellular accumulation of ROS in exposed cells. Taken together, the results of our in vitro study reported herein is consistent with the conclusion that 4-nonylphenol is able to influence hormonal profile, cell viability and generate ROS.

Antioxidant efficiency of lycopene on oxidative stress - induced damage in bovine spermatozoa

Background

Lycopene (LYC) is a natural carotenoid with powerful reactive oxygen species (ROS) scavenging activities. The aim of this study was to investigate if lycopene has the ability to reverse ROS-mediated alterations to the motility, viability and intracellular antioxidant profile of bovine spermatozoa subjected to ferrous ascorbate (FeAA). Spermatozoa were washed out of fresh bovine semen, suspended in 2.9 % sodium citrate and subjected to LYC treatment (0.25, 0.5, 1 or 2 mmol/L) in the presence or absence of FeAA (150 μmol/L FeSO₄ and 750 μmol/L ascorbic acid) during a 6 h in vitro culture. Spermatozoa motion characteristics were assessed using the SpermVision™ computer-aided sperm analysis (CASA) system. Cell viability was examined with the metabolic activity (MTT) assay, ROS generation was quantified via luminometry and the nitroblue-tetrazolium (NBT) test was applied to quantify the intracellular superoxide formation. Cell lysates were prepared at the end of the in vitro culture to investigate the intracellular activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) as well as the concentrations of glutathione (GSH) and malondialdehyde (MDA).

Results

FeAA treatment led to a reduced spermatozoa motility (P < 0.001), viability (P < 0.001) and a decline of the antioxidant capacity of spermatozoa (P < 0.001) but increased the ROS generation (P < 0.001), superoxide production (P < 0.001) and lipid peroxidation (P < 0.001). LYC administration resulted in a preservation of the spermatozoa motion parameters (P < 0.001), mitochondrial activity (P < 0.001) and antioxidant characteristics (P < 0.001 with respect to SOD; P < 0.01 in relation to CAT; P < 0.05 as for GPx and GSH) with a concentration range of 1 and 2 mmol/L LYC revealed to be the most effective.

Conclusions

Our results suggest that LYC exhibits significant ROS-scavenging and antioxidant properties which may prevent spermatozoa alterations caused by oxidative stress, and preserve the functionality of male reproductive cells.

COMPARISON OF TWO COLORIMETRIC ANTIOXIDANT CAPACITY ASSESSMENT METHODS IN BOVINE SEMEN FRACTIONS

The antioxidant capacity represents the concentration and activity of diverse components which prevent oxidative damage to biomolecules. This study compares the effectiveness two routinely available protocols (Total antioxidant status - TAS and Ferric reducing ability of plasma - FRAP) with respect to the relationship between the antioxidant capacity and semen quality in bovine seminal plasma and spermatozoa. Computer assisted semen analysis was used to evaluate selected spermatozoa motion parameters; TAS and FRAP were assessed using UV/VIS spectrophotometry. Higher antioxidant activity (P

IN VITRO EFFECT OF 4-NONYLPHENOL ON cAMP STIMULATED ANDROSTENEDIONE PRODUCTION AND VIABILITY OF MICE LEYDIG CELLS

The toxic effect of various environmental contaminants such as heavy metals or industrial chemicals such as alkylphenolson male reproductive systemwasfound. 4-nonylphenol (4-NP), one of the environmental contaminants used in the manufacture of plastics and other products, is released largely into the environment. The majority of studies on NP have focused on their endocrine disrupting and potential adverse effects on reproductive system. The target of our in vitro study was to determine the potential impact of 4–nonylphenol as an endocrine disruptor on the hormonal secretion and viability of mice Leydig cells. Cells were cultured with addition of 0.04; 0.2; 1.0; 2.5; and 5.0 µg/mL of 4–nonylphenol for 44h and compared with the control. Cells destined for the determination of androstenedione production were cultured in the presence of cyclic AMP solution. Quantification of cAMP stimulated androstenedion production directly from aliquots of the medium was performed by enzyme linked immunosorbent assay (ELISA). The viability of Leydig cells was detected by the metabolic activity (MTT) assay. The cAMP stimulated androstenedione production significantly (P

The Impact of 4-Nonylphenol on the Viability and Hormone Production of Mouse Leydig Cells

Exogenous substances altering the function of the endocrine system and exhibiting adverse health effects on the organism are defined as endocrine disruptors. Nonylphenol is one of the most abundant alkylphenol ethoxylate derivatives, being detected in food products. Diverse studies have classified nonylphenol as hazardous to the health, especially to male reproduction. This in vitro study aimed to examine the effects of 4-nonylphenol on androstenedione and testosterone production as well as on the viability of Leydig cells of NMRI mice. The cells were cultured for 44 h with addition of 0.04; 0.2; 1.0; 2.5 and 5.0 μg/ml of 4-nonylphenol and compared to the control. Quantification of testosterone and androstenedione directly from aliquots of the medium was performed by enzyme-linked immunosorbent assay. Cell viability was measured by the metabolic activity assay for mitochondrial functional activity. Androstenedione production significantly (P < 0.001) increased with 1.0; 2.5 and 5.0 μg/ml 4-nonylphenol. Although cAMP-stimulated testosterone production was not significantly affected by 4-nonylphenol, a tendency to attenuate the level of testosterone in the Leydig cells treated with 2.5 and 5.0 μg/ml 4-nonylphenol was observed. The viability of mouse Leydig cells was slightly increased at the lowest doses of 4-nonylphenol (0.04 and 0.2 μg/ml). We also observed an increase at higher concentrations of the substance (1.0; 2.5 and 5.0 μg/ml), but this increase was not significant. Further investigations are required to establish the biological significance and possible reproductive implications.

Dose- and Time-Dependent In Vitro Effects of Divalent and Trivalent Iron on the Activity of Bovine Spermatozoa

This in vitro study was designed to assess the impact of divalent (Fe(2+)) or trivalent (Fe(3+)) iron on the activity and oxidative balance of bovine spermatozoa at specific time intervals (0, 2, 8, 16, and 24 h) during an in vitro culture. Forty-five semen samples were collected from adult breeding bulls and diluted in physiological saline solution supplemented with different concentrations (0, 1, 5, 10, 50, 100, 200, 500, 1000 μmol/L) of FeCl2 or FeCl3. Spermatozoa motion parameters were assessed using the SpermVision™ computer-aided sperm analysis (CASA) system. Cell viability was examined with the metabolic activity 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the nitroblue-tetrazolium (NBT) test was applied to quantify the intracellular superoxide formation. Both divalent and trivalent iron exhibited a dose- and time-dependent impact on the spermatozoa physiology and oxidative balance. Concentrations ≥50 μmol/L FeCl2 and ≥100 μmol/L FeCl3 led to a significant decrease of spermatozoa motility (P < 0.05) and mitochondrial activity (P < 0.001 with respect to 200-1000 μmol/L FeCl2/FeCl3; P < 0.01 in case of 100 μmol/L FeCl2/FeCl3), accompanied by a significant superoxide overproduction (P < 0.001 in terms of 200-1000 μmol/L FeCl2 and 500-1000 μmol/L FeCl3; P < 0.01 with respect to 100 μmol/L FeCl2 and 100-200 μmol/L FeCl3). On the other hand, concentrations below 10 μmol/L FeCl2 and 50 μmol/L FeCl3 proved to stimulate the spermatozoa activity, as shown by a significant preservation of the motility and viability characteristics (P < 0.001 in case of the motility parameters; P < 0.01 with respect to the spermatozoa viability), alongside a significant decline of the superoxide generation (P < 0.05). In a direct comparison, divalent iron has been shown to be more toxic than trivalent iron. Results from this in vitro study show that high concentrations of both forms of iron are toxic, while their low concentrations may have spermatozoa activity-promoting properties. In vitro concentrations of divalent or trivalent iron that could be regarded as critical are 50 μmol/L FeCl2 and 100 μmol/L FeCl3 when iron ceases to be an essential micronutrient in order to become a toxic risk factor.

Resveratrol offers protection to oxidative stress induced by ferrous ascorbate in bovine spermatozoa

Resveratrol (RES) is a natural polyphenol and phytoestrogen exhibiting cardioprotective, anticancer, antibacterial and vasorelaxing properties. It is also a powerful reactive oxygen species (ROS) scavenger and chelating agent. This study was designed to determine the efficiency of RES to reverse the ROS-mediated impairment of the motility, viability and intracellular antioxidant profile of bovine spermatozoa. Spermatozoa were washed out of fresh bovine semen, suspended in 2.9% sodium citrate and subjected to RES treatment (5, 10, 25 and 50 μmol L(-1)) in the presence or absence of a pro-oxidant, i.e., ferrous ascorbate (FeAA; 150 μmol L(-1) FeSO4 and 750 μmol L(-1) ascorbic acid) during a 6-h in vitro culture. Spermatozoa motion parameters were assessed using the SpermVision computer-aided sperm analysis (CASA) system. Cell viability was examined with the metabolic activity (MTT) assay, and the nitroblue-tetrazolium (NBT) test was applied to quantify the intracellular superoxide formation. Cell lysates were prepared at the end of the in vitro experiments in order to investigate the intracellular activity of superoxide dismutase (SOD), catalase (CAT), as well as the concentrations of glutathione (GSH) and malondialdehyde (MDA). FeAA treatment led to a reduced sperm motility (P < 0.001) and viability (P < 0.001), decreased the antioxidant parameters of the samples (P < 0.001 in case of SOD; P < 0.01 with respect to CAT; P < 0.05 in relation to GSH) but increased the superoxide production (P < 0.001) and lipid peroxidation (P < 0.001). RES supplementation resulted in a preservation of the spermatozoa vitality and antioxidant characteristics (P < 0.001 in case of SOD; P < 0.01 with respect to 25-50 μmol L(-1) RES and P < 0.05 in relation to 10 μmol L(-1) RES; P < 0.05 in case of GSH), with 50 μmol L(-1) RES proving to be the most effective RES concentration. Our results suggest that RES possesses significant antioxidant properties that may prevent the deleterious effects caused by ROS to spermatozoa, and preserve the fertilization potential of male reproductive cells.

ANTIOXIDANT EFFICIENCY OF RESVERATROL ON OXIDATIVE STRESS-INDUCED DAMAGE IN BOVINE SPERMATOZOA

Substantial reports suggest that biologically active compounds isolated from natural sources may offer protection to semen against the incidence of free radical producers, improvement of semen quality, prevention of cryodamage and DNA fragmentation, as well as a general promotion of spermatozoa metabolism. This study was therefore designed to assess the impact of resveratrol (RES), a natural polyphenol and phytoalexin with potential antiviral, anti-inflammatory and antioxidant properties on bovine spermatozoa subjected to oxidative stress induced by ferrous ascorbate during a short-term cell culture (6h). Fresh bovine semen samples were centrifuged, the seminal plasma was removed, the sperm pellet was washed out and the resulting cells were diluted in 2.90% sodium citrate, divided into equal fractions and subjected to treatment based on a specific concentration of RES (50, 25, 10, 5, 0 μmol/L) in the presence of an oxidative stress inducer, i.e. ferrous ascorbate (FeAA) containing 150 μmol/L FeSO4 and 750 μmol/L ascorbic acid. After 6h, the spermatozoa motility (using the Computer-aided sperm analysis/CASA system) and superoxide production (via the NBT test) were assessed in each sample. Furthermore, the sperm cells were collected, lysed and examined for the activity of superoxide dismutase and catalase, as well as glutathione and malondialdehyde concentrations. The addition of RES into the culture medium was able to significantly (P

BIS(2-ETHYLHEXYL) PHTALATE AFFECTS SPERMATOZOA MOTILITY DURING SHORT-TERM IN VITRO CULTIVATION

Bis(2-ethylhexyl) phthalate is ubiquitous in the environment as a results of its widespread manufacture and use, as well as their high concentration in plastics and ability to migrate from them into the air, water and ground, and then enters foodstuffs. The present study evaluated the effects of BEHP at the doses 1, 10, 100 and 200 μg/mL on the motility of bovine spermatozoa during short-term in vitro cultivation. The CASA system with SpermVisionTM program was used to determine the spermatozoa motility. The initial evaluation showed the decrease of motility with significant differences (P 100 μg/mL of BEHP decreased motility significantly (P

The effect of mammary gland-specific transgene expression on rabbit reproductive gland structure

Transgenic rabbits are excellent animal models for human diseases and suitable bioreactors for the production of recombinant proteins on an experimental and commercial scale. The aim of this study was to compare the structure of the mWAP-hFVIII transgenic and non-transgenic rabbit ovarian and testicular tissue. Ovarian and testicular tissue samples were taken from transgenic and non-transgenic New Zealand White rabbits, examined by optical microscopy and analyzed morphometrically. An increase of the relative volume of primary follicles and a decrease of the relative volume of antral follicles was detected in the transgenic ovarian structure (P < 0.05), but other developmental follicular stages and follicular diameters were not affected (P > 0.05). In the testes a significant decrease (P < 0.05) of the epithelial height was detected in the transgenic testicular structure, but the relative volume of all basic structures (germinal epithelium, interstitium and lumen) was unaltered (P > 0.05). Generally, this study demonstrates a weak negative effect of mWAP-hFVIII transgenesis on rabbit gonadal structure.

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.

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.