Natural Sperm Birefringence Can be Used to Estimate Sperm Viability and Morphology

Effects of six kinds of sperm staining methods on human sperm size and evaluation of their staining effects

BACKGROUND

Large- and small-headed sperm are common morphological abnormalities. If different sperm staining methods affect sperm size, they will make a difference in the accuracy of sperm morphological analysis results. In this case, the normal reference values of sperm head parameters for different staining methods should be established.

METHODS

Six sperm staining methods, including Papanicolaou, Diff-Quik, Shorr, Hematoxylin-eosin (HE), Wright, and Wright-Giemsa staining, were used to stain the sperm smears of 25 semen samples, respectively. Sperm head parameter's length (L), width (W), area (A), perimeter, acrosomal area (Ac), and the derived values L/W and Ac/A of 2500 sperm (100 for each specimen) per staining method were measured by a computer-aided sperm morphological analysis system.

RESULTS

The highest sperm head length and width were observed with the Wright-Giemsa and Wright staining, followed by the Diff-Quik. The lowest sperm head length and width were observed with the Papanicolaou staining, and the sperm head length and width of HE and Shorr staining were between those of Papanicolaou and Diff-Quik staining. There was the same trend in changes in sperm head area and perimeter. Diff-Quik and Shorr staining could clearly distinguish acrosome and nucleus, followed by HE staining, whereas the boundary between acrosome and nucleus was not evident in Papanicolaou, Wright, and Wright-Giemsa staining.

CONCLUSION

Different staining methods influence sperm size, and the normal reference values of sperm head parameters of each staining method should be established. Diff-Quik and Shorr staining may be suitable methods for routine sperm morphological analysis.

Combined Raman and polarization sensitive holographic imaging for a multimodal label-free assessment of human sperm function

Raman microspectroscopy (RM) and polarization sensitive digital holographic imaging (PSDHI) are valuable analytical tools in biological and medical research, allowing the detection of both biochemical and morphological variations of the sample without labels or long sample preparation. Here, using this multi-modal approach we analyze in vitro human sperm capacitation and the acrosome reaction induced by heparin. The multimodal microscopy provides morphofunctional information that can assess the sperms ability to respond to capacitation stimuli (sperm function). More precisely, the birefringence analysis in sperm cells can be used as an indicator of its structural normality. Indeed, digital holography applied for polarization imaging allows for revelation of the polarization state of the sample, showing a total birefringence of the sperm head in non-reacted spermatozoa, and a birefringence localized in the post-acrosomal region in reacted spermatozoa. Additionally, RM allows the detection and spectroscopic characterization of protein/lipid delocalization in the plasma and acrosomal membranes that can be used as valuable Raman biomarkers of sperm function. Interestingly, these spectral variations can be correlated with different time phases of the cell capacitation response. Although further experimentation is required, the proposed multimodal approach could represent a potential label-free diagnostic tool for use in reproductive medicine and the diagnosis of infertility.

The clinical and neonatal outcomes after stimulation of immotile spermatozoa using SperMagic medium

To evaluate the efficiency and safety of SperMagic medium on stimulating the immotile spermatozoa in testicular sperm extraction (TESE) and absolute asthenozoospermia, 96 patients with TESE and 106 patients with absolute asthenozoospermia were enrolled in this study. The motile spermatozoa were detected in 47 TESE patients and 68 absolute asthenozoospermia and these patients were assigned to control group. The immotile spermatozoa in 49 TESE patients and 34 absolute asthenozoospermia were stimulated with SperMagic medium. Patients were treated by standard intracytoplasmic sperm injection (ICSI). There were no significant differences in fertilisation, cleavage, implantation, pregnancy, live birth and neonatal outcomes. SperMagic medium does not increase incidence of adverse neonatal outcomes and is a reliable tool for selection of viable spermatozoa in ICSI.

Light, polarizing, and transmission electron microscopy: three methods for the evaluation of sperm quality

Semen from 33 patients were evaluated by light microscopy (LM) obtaining sperm concentration, percent motility, percentage of sperm with normal morphology (PAP staining), and percentage of dead sperm (Eosin Y stained). The samples were observed by polarizing microscopy (PM), that evaluates sperm morphology and the viability by birefringence of organelles, and it provides a PM index (percentage of birefringent, viable, motile sperm) and a percentage of dead, non-birefringent sperm. Sperm were processed for transmission electron microscopy (TEM) and TEM data were elaborated with a mathematical formula able to provide a fertility index (FI, number of sperm free of structural defects) and percentages of sperm immaturity and necrosis (dead sperm). To test the reliability of these techniques, the values of normal acrosome, nucleus, midpiece, and tail and the presence of cytoplasmic residues obtained with the three methods were compared. With the exception of cytoplasmic residues (P = 0.40), significant differences in the evaluation of each organelle were observed and TEM analysis resulted as the most stringent screening. In addition, relationships among relevant sperm variables were investigated. Motility showed positive correlations with the percentage of normal tail, midpiece, and PM index (P < 0.01), but it exhibited negative correlations with indices of sperm death (non-birefringent sperm: P < 0.05; percentage of eosin Y stained sperm: P < 0.05; necrosis: P < 0.01), which were positively correlated with each other (P < 0.01). Positive correlations were found between indices expressing normal sperm morphology: FI with PM index (P < 0.01) and with the percentage of normal sperm (PAP staining) (P < 0.01), which in turn were correlated with the PM index (P < 0.001). Sperm immaturity showed positive correlations (P < 0.01) with the presence of cytoplasmic residues detected with the three methods. In conclusion, LM, PM, and TEM are reliable techniques in evaluating sperm quality. PM appears to offer several advantages 'midway' between LM and TEM and it should be considered in sperm analysis.

Evaluation of ubiquitin and annexin V in sperm population selected based on density gradient centrifugation and zeta potential (DGC-Zeta)

PURPOSE

Sperm that bypass natural apoptosis and the ubiquitin-proteasome system may find their way into semen. In order to avoid the insemination of such sperm during an intracytoplasmic sperm injection (ICSI) treatment, novel sperm selection procedures such as the Zeta procedure have been implemented. Therefore, the aim of this study was to evaluate extent of ubiquitination and external phosphatidylserine (EPS) in sperm populations selected by combines density gradient centrifugation (DGC) and Zeta electric potential in comparison to DGC and neat semen samples.

METHODS

Semen samples were collected from 51 infertile men and divided into control, DGC and DGC-Zeta groups. Semen analysis was carried out according to World Health Organization criteria. The percentages of protamine deficiency, DNA fragmentation, EPS and ubiquitinated sperm were assessed by chromomycin A3 (CMA3), TUNEL, Annexin V, and immunostaining, respectively.

RESULTS

Sperm selected by the DGC-Zeta procedure presented a lower percentage of sperm with protamine deficiency, abnormal morphology and DNA fragmentation while the percentage of annexin V and ubiquitin-positive sperm increased.

CONCLUSION

The results of this study reveal that, DGC-Zeta improves the quality of the selected spermatozoa for ICSI and increases ubiquitination and EPS rates. We propose these alterations are part of the normal physiological process of capacitation.

Absolute asthenozoospermia and ICSI: what are the options?

BACKGROUND

Complete asthenozoospermia, i.e. 100% immotile spermatozoa in the ejaculate, is reported at a frequency of 1 of 5000 men. Its diagnosis implies a poor fertility prognosis even with ICSI. It is extremely important to distinguish between two different groups of patients with complete asthenozoospermia, i.e. virtual or absolute asthenozoospermia. With the former group having some motile spermatozoa after extensive processing of the semen, absolute asthenozoospermia can be associated with metabolic deficiencies, ultrastructural abnormalities of the sperm flagellum, necrozoospermia otherwise it can be idiopathic. In the management of persistent absolute asthenozoospermia, it is very important to elucidate its nature and whenever possible to correct the potential causes.

METHODS

We reported data published in the literature on the aetiology of absolute asthenozoospermia and the different techniques to improve ICSI outcome. We propose an algorithm for diagnosis and treatment of this condition. RESULTS Different results regarding fertilization, cleavage and pregnancy rate have been published in patients with absolute asthenozoospermia undergoing ICSI. However, the results vary widely depending on the sperm origin and the technique applied for immotile sperm selection. The percentage of viable spermatozoa varies between 0 and 100%.

CONCLUSIONS

Absolute immotile spermatozoa is one of the most important causes of reduced fertilization and pregnancy rates after ICSI and different techniques are used to improve ICSI outcomes. However, it still remains unclear which is the best technique to improve the pregnancy outcomes in these couples.