Comparison of the resazurin test, adenosine triphosphate in semen, and various sperm parameters

Effect of Filgrastim on adult male rats' fertility and reproductive performance

Filgrastim is a recombinant protein used in treatment neutropenia caused by myelosuppressive medications for patients with non-myeloid cancer. However, its effect in male fertility is not clear. So, the current work aims to clarify the effect of Filgrastim on the reproductive state in Wistar rats. Eighteen (18) male Wistar rats were divided into three groups (6/each). Group (I) where the rats were injected with 0.5 ml/kg/day of distilled water and served as Control Group. The Group (II) animals received intraperitoneal injection of therapeutic dose of 30.83 mcg/kg/day of Filgrastim for one week. The Group (III) rats received the same dose by the same route of Filgrastim for two weeks. Sera of blood samples were processed for serum follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone (TS). Semen analysis and resazurine reduction test (RRT) were performed. Assaying for malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) was done. The testes were retrieved for histopathological and immunohistochemical studies for caspase-3 detection. Our results revealed that filgrastim affects sperm morphology, significantly decreased the RRT and the reproductive hormones level, elevated the oxidative stress status and induced several histopathological changes in testes with an increased in immunoexpression of caspase-3 in testes tissues. The results of this work demonstrated that Filgrastim may had a deleterious effect on male fertility.

Metabolic activity of sperm cells: correlation with sperm cell concentration, viability and motility in the rabbit

The resazurin reduction test (RRT) is a useful technique to assess the metabolic rate of sperm cells. RRT depends on the ability of metabolically active cells to reduce the non-fluorescent dye resazurin to the fluorescent resorufin. The aim of this study was to develop a vital fluorometric method to evaluate metabolic activity of rabbit sperm cells. Twenty-five rabbit males were included in the study. Viability and morphology, motility and metabolic activity were evaluated using an eosin-nigrosin staining, a computer-assisted semen analysis (CASA) and the RRT, respectively. Spearman rank correlation analysis was used to determine the correlation between RRT and semen parameters. After evaluation, a concentration of 10 × 106 sperm cells/ml was selected for further experiments with RRT. No significant correlation was found between the RRT results and the motility parameters. However, after RRT a significant positive correlation between relative fluorescence units and the percentage of alive spermatozoa (r = 0.62; P = 0.001) and a negative one with the percentage of sperm cells with acrosomic abnormalities (r = -0.45; P < 0.05) were detected. The vital assessment of metabolic rate of sperm cells by RRT could provide more information about semen quality than other routine semen analysis, correlating with sperm viability and acrosome status information.

Electrochemical study of Alamar Blue (resazurin) in aqueous solutions and room-temperature ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate at a glassy carbon electrode

Electrochemical behaviour of resazurin in aqueous buffered solutions and ionic liquid was studied. The orientation of adsorbed resazurin was estimated. It is found that, the orientation of the adsorbed resazurin at glassy carbon surface is edgewise.

Gelatinases in Boar Seminal Plasma and Their Relation to Semen Indicators

Matrix metalloproteinases were detected in reproductive tissues and seminal plasma of various animal species. The aim of this study was to determine for the first time the presence of gelatinases and metalloproteases in boar seminal plasma and to correlate the results with semen indicators. Gelatin zymography was used for simultaneous identification and measurement of gelatinase enzyme activity associated with their molecular weights. Several gelatinase forms were identified in seminal plasma of boars. Those that were stimulated by CaCl2 and inhibited by EDTA and phenanthroline were considered as metalloproteases. Negative correlation between semen indicators (sperm index, sperm concentration and concentration of progressive motile sperm) and the concentrations of metalloprotease at 78 kDa and 66 kDa means that higher values of semen indicators correlate with lower concentrations of these metaloproteases in seminal plasma. Gelatinases with molecular weight of 225, 78 and 66 kDa correlated with higher levels of acrosome damage. Samples with sperm index above 110 M/ml contained gelatinases of significantly lower band intensities at 78 and 66 kDa compared to samples with SI less than 110 M/ml. Bands with 225, 78 and 66 kDa are suggested to belong to a dimer of MMP-9, proMMP-2 and mature MMP-2.

Determination of the diagnostic value of the resazurin reduction assay for evaluating boar semen by receiver operating characteristic analysis

AIM

To assess that metabolic status of spermatozoa could provide a useful tool for evaluation of semen quality.

METHODS

The accuracy of the spectrophotometric application of the resazurin reduction assay was assessed using receiver operating characteristic (ROC) analysis.

RESULTS

Areas under ROC curves (AUC) for motile sperm concentration and sperm index (SI) (sperm concentration multiplied by the square root of percentage sperm motility multiplied by the percentage normal sperm morphology) were 0.922. The best discrimination between poor and good semen samples according to the SI was achieved at a cut-off point of A610 = 0.209, where high sensitivity (94.1%) and specificity (91.7%) were calculated. The assay was less accurate when motile sperm concentration was used as the criterion value, yielding sensitivity of 88.2% and specificity of 87.5%, respectively. Likelihood ratios (LR) indicate that absorbances lower than 0.209 were at least 11.3 times as likely to be found in good semen samples than those in poor according to the SI, whereas in the case of motile sperm concentration, the LR was calculated to be 7.06.

CONCLUSION

These results show that the resazurin reduction assay combined with spectrophotometry is an accurate method of assessing the quality of boar semen.

Spectrophotometric application of resazurin reduction assay to evaluate boar semen quality

The resazurin reduction assay depends on the ability of metabolically active cells to reduce the resazurin redox dye to resorufin. In the present study we applied and made a diagnostic evaluation of a spectrophotometric application of the resazurin reduction assay to assess the colour change of resazurin reduction in butanol extracted colour to evaluate boar semen quality. Forty-one samples of boar semen from various breeds were included in the study. The absorption peaks for resazurin and resorufin were found to be 610 and 575 nm, respectively. Absorbance at 610 nm, where the minimum overlap of the two peaks was observed, was used in further analysis. Spearman rank correlation analysis was used to determine the correlation between the resazurin reduction assay and various semen parameters. The highest correlations were observed with the concentration of motile spermatozoa (r = -0.841; p < 0.001), sperm concentration (r = -0.833; p < 0.001), sperm index (-0.826; p < 0.001) and concentration of viable spermatozoa (r = -0.763; p < 0.001). Sensitivity and specificity, at 94.1 and 91.7%, respectively, indicate that the present test is highly accurate in discriminating between the samples according to the sperm index. When motile sperm concentration was used to distinguish between good and poor samples, high sensitivity (93.6%) was also found, whereas the test was only moderately, 80%, specific. The stability of butanol extracts in terms of A610 at different times of measurement confirmed that the resazurin reduction could be spectrophotometrically measured within 7 days from the time of assay performance, making the assay much more useful. Based on these results, the assay could be used as an additional tool for evaluating the quality of boar semen.

The correlates and alleged biochemical background of the resazurin reduction test in semen

Reduction of the blue dye resazurin to pink resorufin is used to estimate the concentration of metabolically active spermatozoa in semen samples. In order to quantify the reduction of resazurin, a spectrophotometric method was developed measuring the change from blue to pink in the butanol extracted colour. The biochemical mechanisms involved in the reduction of resazurin by motile spermatozoa and seminal plasma were investigated. Addition of NADH + H+ to sperm suspension or seminal plasma increased the reduction of resazurin. The reduction reaction was inhibited by high concentrations of dicoumarol, a specific inhibitor of the diaphorase enzyme, in a dose-dependent manner. It is suggested that the sperm diaphorase enzyme transfers electrons from NADH + H+ to resazurin, reducing it to resorufin. The degree of resazurin reduction was strongly correlated with the concentration of motile spermatozoa recovered from the 90% Percoll fraction (r = 0.98, p < 0.001). A positive correlation was also found between the reducing capacity of seminal plasma (n = 62) on the one hand, and sperm concentration (r = 0.72, p < 0.0001), progressive motility (r = 0.45, p < 0.01), normal morphology (r = 0.50, p < 0.01), and gamma-glutamyltransferase (r = 0.36, p < 0.05) on the other hand. These findings, together with our previous observations that the reduction reaction is inhibited by reactive oxygen species and polymorphonuclear white blood cells, increase our understanding of the biochemical basis of the resazurin test and may provide better insight into the interpretation of this test.

Mechanisms of sperm deficiency in male accessory gland infection

The presence of 2 million or more peroxidase-positive white blood cells per ml of semen, or the diagnosis of male accessory gland infection, is associated with important biochemical and biological changes in semen plasma and in the spermatozoa, reducing their fertilizing potential in vitro and in vivo (e.g., during intra-uterine insemination). In addition to the effects of reactive oxygen species, and its influence on the essential fatty acid composition of the sperm membrane, potentially unfavourable effects can occur through the intermediate of increased concentrations of certain cytokines, and decreased activity of enzymes such as alpha-glucosidase. In contrast, lower numbers of white blood cells may exert beneficial effects on spermatozoa thanks to the increased production of hepatocyte growth factor/scatter factor (a tissue repairing substance), and the stimulation of immuno-competent cells by particular cytokines (e.g., Interleukin-6).

Effects of resazurin on bovine oocyte fertilization and embryo development in vitro

Resazurin is a redox dye (7-hydroxy-3H-phenoxazin-3-one-10-oxide) used for assessing potential fertility of spermatozoa and functional status of eukaryotic cells. In this study, the fertilizing capacity of spermatozoa treated with resazurin and effects of resazurin on bovine embryo development in vitro was examined. Abattoir-derived bovine oocytes were collected and subjected to in vitro maturation (IVM), fertilization (IVF) and culture (IVC). In Experiment 1, bovine oocytes (n = 2767) were fertilized with spermatozoa exposed to resazurin (17.6 micrograms/ml) for 0, 15, 30, 60 min, respectively. There was no significant (P > 0.05) difference in cleavage rates. However, the proportion of embryos that developed into blastocysts, expanded and hatched blastocysts in those groups in which oocytes/embryos were treated with resazurin during IVC or IVM/IVF/IVC was significantly (P < 0.05) less than those exposed to resazurin during IVM only, or during IVF only. We conclude that resazurin did not have significant adverse effects on fertilizing capability of bovine spermatozoa; however, extended treatment of embryos with resazurin may be detrimental to embryonic development.

Performance of the sperm quality analyser in predicting the outcome of assisted reproduction

The present study was undertaken to assess the relationship between the results of conventional semen analysis and the sperm motility index (SMI) as measured by the sperm quality analyser (SQA), and to evaluate these in relation to the fertilization and/or pregnancy outcome of assisted reproduction. SMI determinations and conventional semen analyses were performed on 223 samples from subfertile men in two laboratories in Leuven (n = 136) and Antwerp (n = 87), and on spermatozoa prepared on a Percoll gradient (n = 136) used for treatment of male factor infertility in 57 cycles of intrauterine insemination (IUI), 44 attempts at in vitro fertilization (IVF) and 31 attempts at intracytoplasmic sperm injection (ICSI). SMI values for native semen correlated significantly with sperm concentration, motility and morphology. Multiple regression analysis revealed sperm concentration after preparation, and the concentration of motile spermatozoa with normal morphology and SMI (before preparation) to be the independent determinants for SMI after preparation. SMI values were significantly higher after, than before, preparation (p < 0.0001). In regular IVF (n = 44) the percentage of fertilized oocytes correlated significantly (p < 0.05) with sperm motility (A + B%, r = 0.33), with the percentage of spermatozoa with normal morphology (r = 0.46) before preparation, with the values of SMI both before and after preparation (r = 0.54, r = 0.48), with sperm concentration (r = 0.34) and with the motile sperm concentration (r = 0.29) after preparation. For the occurrence of pregnancy (all treatment methods), comparison of areas under ROC curves (AURC) indicated motile sperm concentration after preparation, as well as SMI both before and after preparation, to have the highest AURC, with no significant difference between these values as far as predictive power was concerned. These results indicate that the SQA allows for rapid evaluation of sperm characteristics and of the effectiveness of sperm preparation techniques. However, it is not superior to conventional semen analysis in predicting the outcome of assisted reproduction.