Sperm head vacuoles are not affected by in-vitro conditions, as analysed by a system of sperm-microcapture channels

The effect of pentoxifylline and calcium ionophore treatment on sperm cell biology in oligoasthenoteratozoospermia samples

The objective of this study was to assess the effects of pentoxifylline (PTX) and Ca²⁺ ionophore (CI) A12387 treatment on some biological characteristics of sperm cells in oligoasthenoteratozoospermia (OAT) patients. After processing, each sample was divided into four groups: 1, control; 2, exposed to 3.6 mM PTX; 3, exposed to 5 μm calcium ionophore (CI); and 4, exposed to both PTX and CI; 30 min at 37°C. Sperm motility was measured before and after preparation. Acrosome reaction (AR), status of sperm vacuoles, mitochondrial membrane potential (MMP) and DNA fragmentation were assessed using PSA-FITC staining, motile sperm organelle morphology examination (MSOME), JC-1 staining and sperm chromatin dispersion (CSD) test, respectively. Treatment with PTX and CI led to increased and decreased sperm motility, respectively (P < 0.05). Furthermore, vacuole status and rates of sperm DNA fragmentation were not significantly different among groups (P > 0.05). Moreover, the data showed that the rates of AR and disrupted MMP were significantly different between groups (P < 0.05). In conclusion, in vitro application of PTX not only did not have any adverse effects on sperm cell biology characteristics, but also can rectify the harmful effect of CI.

Sperm nuclear vacuoles in relation to acrosome reactions and sperm motility

We investigated sperm nuclear vacuolation in relation to acrosome reactions and the maintenance of sperm motility. Thirty male patients who visited our Male Infertility Clinic were enrolled. These patients underwent conventional semen analyses, Acrobeads tests, and high-magnification observation of the sperm head to evaluate the degree of nuclear vacuolation on the Acrobeads test scoring after 24 hours of incubation. The presence of acrosome reactions was evaluated using the Acrobeads test. The spermatozoa were classified into three groups: (I) those bound to MH61-beads, (II) motile spermatozoa that did not bind to MH61-beads, and (III) immotile spermatozoa that did not bind to MH61-beads. The percentage of spermatozoa with large nuclear vacuoles (%LNV) was compared between the three groups. The degree of sperm nuclear vacuolation was evaluated in 17,992 ejaculated spermatozoa. The mean %LNVs were 2.4% in group I, 5.8% in group II, and 9.8% in group III. These values were significantly different from each other (P < 0.001, paired t-test). There were no correlations between the %LNV values and the Acrobeads scores. In conclusion, the degree of sperm nuclear vacuolation was significantly lower in the acrosome-reacted spermatozoa and spermatozoa with maintained motility, and higher in the immotile spermatozoa that did not bind to MH61-beads.

The nature of human sperm head vacuoles: a systematic literature review

Motile sperm organelle morphology examination (MSOME) involves the use of differential interference contrast microscopy (also called Nomarski contrast) at high magnification (at least 6300x) to improve the observation of live human spermatozoa. In fact, this technique evidences sperm head vacuoles that are not necessarily seen at lower magnifications - particularly if the vacuoles are small (i.e. occupying <4% of the sperm head’s area). However, a decade after MSOME's introduction, it is still not clear whether sperm head vacuoles are nuclear, acrosomal and/or membrane-related in nature. In an attempt to clarify this debate, we performed a systematic literature review in accordance with the PRISMA guidelines. The PubMed database was searched from 2001 onwards with the terms "MSOME", “human sperm vacuoles”, "high-magnification, sperm”. Out of 180 search results, 21 relevant English-language publications on the nature of human sperm head vacuoles were finally selected and reviewed. Our review of the literature prompted us to conclude that sperm-head vacuoles are nuclear in nature and are related to chromatin condensation failure and (in some cases) sperm DNA damage.

Observation of spermatozoa by a high-magnification microscope

Semen analyses are the primary tool for evaluating male infertility, as semen parameters are useful for predicting potential fertility. In the field of assisted reproductive technology (ART), the single best motile spermatozoon should be selected, especially when performing intracytoplasmic sperm injection (ICSI). In this context, the motile sperm organelle morphology examination (MSOME) was developed as a method of assessing the detailed morphology of motile spermatozoa in real time at a magnification of up to 6,300× on a video system. The use of ICSI with MSOME-selected sperm is called intracytoplasmic morphologically selected sperm injection (IMSI). IMSI improves the outcomes of ICSI. MSOME can be also applied to evaluate male infertility. Among MSOME parameters, the presence of sperm nuclear vacuoles is the most important finding. Large sperm nuclear vacuoles (LNV) are related not only to poor ART outcomes, but also to poor semen quality and sperm DNA damage, such as DNA fragmentation and chromatin condensation failure. It has been suggested that sperm head vacuoles are produced at earlier stages of sperm maturation. It is possible that the number of LNV can be decreased by surgical or medical treatment for male infertility. Therefore, the level of LNV has the potential to be used as an alternative parameter of semen quality and a new tool for evaluating the therapeutic effects of treatment in male patients with infertility.