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Aim. To perform comparative analysis of sperm characteristics and DNA fragmentation in men vaccinated with GamCOVID-Vac (Sputnik V) and unvaccinated men.Materials and methods. Characteristics ofsemen analysis and DNA fragmentation index in ejaculate samples of 122 men, 28 of whom were vaccinated with Gam-COVID-Vac (Sputnik V), were analyzed. Study participants did not have history of coronavirus infection COVID-19. Vaccinated patients were divided into 2 groups: group 1 (n = 10) included patients for whom the time between full vaccination (2 doses of the vaccine) and ejaculate sampling was shorter than 75 days; and the group 2 (n = 18) included patients for whom the time between vaccination and ejaculate sampling was longer than 75 days. Unvaccinated men comprised the control group (group 3, n = 94). Standard semen analysis was performed in accordance with the accepted laboratory guidelines of the World Health Organization (2010). DNA fragmentation was evaluated using fluorescent labelling of single- and double-strand DNA breaks (TUNEL).Results. Totalsperm countin the group 1 was 265 ± 75 million, in the group 2 – 355 ± 67 million, in the group 3 – 304 ± 26 million. Progressive motile (PR)sperm in the group 1was 18.5 ± 1.9 %, in the group 2 – 23.2 ± 3.0 %, in the group 3 – 18.2 ± 1.1 %. Normal sperm morphology in the group 1 was 4.0 ± 0.5 %, in the group 2 – 5.8 ± 0.9 %, in the group 3 – 4.1 ± 0.3 %. The best ejaculate quality was observed in patients of the group 2, however, no statistically significant differences in semen analysis characteristics between the groups were found. Percentage of sperm with fragmented DNA (DNA fragmentation index, DFI) in the group 1 varied between 4.6 and 31.4 %, in the group 2 between 0.8 and 36.5 %, in the group 3 (control) between 1.3 and 39.8 %. Mean number of germ cells with DNA breaksin the group 1 (12.5 ± 2.4 %) was higher than in the group 2 (10.9 ± 2.0 %) and control group (10.5 ± 0.7 %), but with no statistical significance. Percentage of patients with DNA fragmentation index above the reference value (≤15 %) in the groups 1, 2 and 3 was 20, 22 and 18 % respectively. In 3 of 6 patients with increased DFI in the groups 1 and 2, this value was above the reference level even before vaccination.Conclusion. No significant effect of vaccination with Sputnik V on sperm DNA fragmentation level in men was observed.

Background. Robertsonian translocations (RTs) are the most common type of balanced chromosomal abnormalities. RT male carriers have an increased risk of reproductive disorders, but the causes of this still are not clear enough.Aim. To evaluate semen parameters in RT(13;14) male carriers.Materials and methods. 24 men with 45,XY,der(13;14)(q10;q10) karyotype and infertility (n = 23) or recurrent pregnancy loss in spouse (n = 1).Results. Oligoasthenoteratozoospermia was detected in 18 (75 %) patients, asthenoteratozoospermia in 3 (13 %) patients, and azoospermia in 2 (8 %) patients. Normozoospermia was detected in 1 (4 %) patient, whose wife had a history of recurrent pregnancy loss.Conclusion. Infertility in the examined RT male carriers is associated with spermatogenesis disorders, in most cases resulted in oligozooasthenoteratozoospermia.

Aim. To compare sperm parameters and the DNA fragmentation in patients after the COVID-19 infection and in men without a history of infection.Materials and methods. Sperm parameters and DNA fragmentation index were evaluated in 172 patients examined in 2020–2022. Based on the data on COVID-19 infection in the anamnesis, the patient’s cohort was divided into three groups: group 1 (n = 16) and group 2 (n = 65) – patients who had an infectious disease less than 75 days and more than 75 days before the delivery of the ejaculate, respectively, and group 3 (control, n = 91) – men have no coronavirus infection. A standard semen examination was performed according by the WHO guidelines (2010) recommendation. Sperm DNA fragmentation was evaluated by fluorescent labeling of single- and double-strand DNA breaks (TUNEL method).Results. The percentage of spermatozoa with fragmented DNA in group 1 varies from 2 to 48 %, in group 2 – from 0.9 to 39 %, in group 3 (control group) – from 1.3 to 52.9 %. The average number of gametes with DNA breaks in group 1 (11.7 ± 3.3 %) is greater than in group 2 (10.6 ± 0.8 %) and in group 3 (10.7 ± 0.8%), but without a statistically significant differences. The proportions of patients whose DNA fragmentation index exceeds the reference value (≤15 %) in groups 1, 2 and 3 are 18.8; 13.8 and 18.7 %, respectively. The count of progressively motile (PR) and morphologically normal spermatozoa in group 2 is statistically significantly greater than in group 3 (22.5 ± 1.6 % vs 18.0 ± 1.2 % and 5.52 ± 0.47 % vs 4.03 ± 0.31 %, respectively).Conclusion. The content of sperm with fragmented DNA is higher in men examined less than 75 days after COVID-19 disease, than in patients, examined more than 75 days after COVID-19 and in men who have no history of this infection. In group 1 an increased DNA fragmentation index was noted mainly in patients who had suffered from the disease in a moderate form.

Introduction. Obtaining spermatozoa in azoospermic men is a relevant objective. Quantitative karyological analysis of immature germ cells (QKA IGCs) allows to characterize the progression of spermatogenesis through different meiotic stages, that present some advantages in comparison with standard semen analysis (SSA) examination and testicular biopsy.The study objective was to analyze SSA and QKA IGCs for detecting of germ cells in the ejaculate of patients with suspected azoospermia.Materials and methods. The ejaculate samples of 20 men with suspected azoospermia of various etiology (genetically determined and idiopathic male infertility) were studied. The ejaculate samples were processed in parallel by two methods, SSA performed according to the WHO laboratory manual for the examination and processing of human semen (2010) and QKA IGCs.Results. Using by the SSA, cryptozoospermia was detected in 1 (5 %) of 20 ejaculate samples. QKA IGCs revealed cryptozoospermia in 10 (50 %) samples, including 53 % of patients (with azoospermia according to SSA). The number of spermatozoa in the ejaculate sediment as a result of QKA IGСs (2.25 ± 4.22) is higher (p = 0.019; U = 113) than the number of spermatozoa as a result of the SSA – 0.25 ± 1.12.Conclusion. In patients with suspected azoospermia, the effectiveness of detecting cryptozoospermia using the QKA IGCs method is significantly (10 times) higher than the SSA. This method complements SSA and makes it possible to detect non-invasively the meiosis defects, including cases with an extremely low concentration of spermatozoa. The analysis is safe for the patient and can be performed repeatedly to track the dynamics of semen parameters.

Introduction. The number of immature germ cells (IGCs) in ejaculate and the ratio of these cells at different stages of their differentiation can reflect meiotic progression and the state of spermatogenesis. Quantitative karyological analysis of immature germ cells from the ejaculate (QKA IGCs) makes it possible to distinguish and analyze all the stages of cell differentiation during spermatogenesis.Purpose. To analyze the spermatogenesis in men with impaired fertility and possible correlation between semen analysis and QKA IGCs parameters. Materials and methods. We analyzed 52 semen samples with normal sperm concentration, normal ejaculate volume and pH. Sperm examination according to WHO criteria and QKA IGCs from the ejaculate were performed (patent of L.F. Kurilo No. 2328736, 2007). According to the number of leukocytes, we divided two groups: a group with normal concentration of leukocytes in the ejaculate (group 1, n = 34) and a group with leukospermia (group 2, n = 18).Results. Increased IGCs index was found in 56 % of the samples in group 1 and 61 % of the samples in group 2. A positive statistically significant correlation was found between the number of spermatocytes I and sperm concentration (group 1), as well as the number of spermatocytes I and morphologically normal spermatozoa (group 2). The average number of non-divided spermatids in group 2 was statistically higher than in group 1. A negative statistically significant correlation was found between the number of non-divided spermatids and the number of morphologically normal spermatozoa, as well as the concentration of germ cells (group 2). Increased IGCs index was found in both pathozoospermia and normozoospermia.Conclusions. The QKA IGCs is an independent method for spermatogenesis evaluation and can be recommended as part of the protocol for examining men with reproductive disorders along with standard semen analysis.

The study objective is to evaluate reproductive function in men who underwent vaccination with Sputnik V (Gam-COVID-Vac) based on quantitative and qualitative sperm characteristics.Materials and methods. Mean ejaculate characteristics were analyzed in 3 independent groups formed from patients examined at the Laboratory of Genetics of Impaired Reproduction of the Research Center for Medical Genetics in 2021: the comparison group consisted of 759 unvaccinated men; the group of 73 men who were vaccinated with Sputnik V and for whom the time between the full vaccination (2 components of the vaccine) and semen analysis was less than 75 days; and the group of 58 men who underwent vaccination more than 75 days prior to semen analysis.The results of semen analysis of 53 patients before and after full vaccination procedure were compared. In 32 patients, less than 75 days passed since vaccination; in 21 patients, more than 75 days; for 5 patients data prior to 75 days since vaccination and after are available.The study group included patients without history of COVID-19. Standard semen analysis was performed in accordance with the World Health Organization Guidelines. For statistical analysis of the differences between the groups Student's t-test was used with significance level of p

Introduction. The risk of infection with SARS-CoV-2 virus and potential cross-infection in an in vitro fertilization laboratory remains unclear. SARS-CoV-2 enters the body through angiotensin-converting enzyme 2 receptor. There is a possibility that high expression of angiotensin-converting enzyme 2 on testicular cells can lead to spermatogenesis disfunction and decreased quality of the ejaculate.The study objective is to compare quantitative and qualitative sperm characteristics in patients who sought medical help at the Laboratory of Genetics of Reproductive Disorders at the Research Centre for Medical Genetics with reproduction problems between 2017 and 2020 with a focus on the period of COVID-19 pandemic.Materials and methods. Results of semen analysis of 4403 patients (mean age 34 years) were considered. Taking into account histories of patients examined in 2020, a separate group of 428 men was formed with 42 men with a history of coronavirus infection confirmed by lab tests (40 cases of mild disease, 2 cases of moderate disease). In 14 patients, sperm analysis was performed twice: prior to COVID-19 and after. Standard sperm analysis was performed in accordance with the World Health Organization Guidelines. For statistical analysis Student’s t-test was used with significance level p

Introduction. The effect of polymorphic variants of the androgen receptor gene (AR) on spermatogenesis and semen parameters in men with different genotypes for other loci has not been sufficiently studied.The aim of this work was to study the effect of the (CAG)n polymorphism of the AR gene on semen parameters in men with impaired fertility, with and without partial deletions of the AZFс region from the Y chromosome.Materials and methods. The study included 988 unrelated Russian patients with pathozoospermia, including 591 patients without Y chromosome microdeletions and 397 patients with partial deletions of the AZFc region of the Y chromosome. The control group consisted of 131 normozoospermic men. All men who participated in the study underwent semen analysis and genetic testing. Genomic DNA was isolated from peripheral venous blood lymphocytes and ejaculate. The analysis of the polymorphism of (GAG)n repeat in exon 1 of the AR gene was performed using a polymerase chain reaction by the amplified fragment length polymorphism method.Results. Three groups were studied: patients with pathozoospermia with (n = 32) and without (n = 541) Y chromosome microdeletions, and normozoospermic men (control, n = 131). The median and quartiles of the number of CAG repeats in the groups were 22 and 20-25, respectively. According to the number of trinucleotide repeats of the AR gene, all patients were divided into subgroups: carriers of short ((GAG)n ≤18), medium ((GAG)n = 19-25) and long ((GAG)n ≥26) alleles. Medium alleles prevailed in all groups; in men without AZFc deletions and with microdeletions, their frequency was 79.3 and 81.4 %, respectively, in controls - 81.7 %.Conclusion. No correlation was found in examined cohort for semen parameters (sperm concentration and total number, number of live, progressively motile and morphologically normal spermatozoa) from the number of trinucleotide repeats. However, a statistically significant difference (p ≤0.045; FDR correction) was found in concentration and total number, number of live, progressively motile and morphologically normal spermatozoa when comparing men with nomrozoospermia (control) with patients with pathozoospermia with and without partial AZFc deletions in subgroups of carriers of short, medium and long alleles.

The study objective is to evaluate the semen parameters, quantitative and qualitative characteristics of spermatozoa, sperm ultrastructure and chromatin status in cystic fibrosis patients with preserved seminal ducts.Materials and methods. We examined 5 cystic fibrosis patients without bilateral obstruction of the vas deferens. Patients underwent standard semen analysis, quantitative karyological analysis of immature germ cells from the ejaculate sediment and transmission electronic microscopy of spermatozoa.Results. Of 5patients, 2 were asthenoteratozoospermic, 1 patient was oligoastenozoospermic, 2patients were asthenozoospermic and 1 was normozoospermic. Oligospermia was detected in 2 samples; increased viscosity of ejaculate was in 1 sample. The pH of the ejaculate was 7.0—7.8; the fructose of the ejaculate was low in one of 2 examined samples. However, oligospermia and low fructose concentration are only indirect signs of aplasy/hypoplasy to the seminal vesicles, since these patients did not perform instrumental visualization of the prostatove-sicular complex. Signs of partial meiotic arrest were revealed in all patients examined using quantitative karyological analysis of immature germ cells. An increased number of abnormal sperm heads, activated acrosomes, an increased content of "immature" chromatin in sperm nuclei were found by transmission electronic microscopy. Sperm DNA fragmentation was increased (32 %, normal range

The study objective is to evaluate the antioxidant potential of seminal plasma in normozoospermia and asthenozoospermia.Materials and methods. Samples of ejaculate from 57 men of reproductive age were studied. Standard spermiologic examination and determination of the antioxidant potential of the seminal fluid using an original chemiluminescent method were performed. The method allowed to measure duration of the latent period from the moment of a decrease in luminescence of the solution containing reactive oxygen species (ROS) after addition of the seminal fluid until the most dramatic increase in luminescence corresponding to decreased antioxidant effect of the seminal fluid.Results. In the samples, the latent time varies from 4.6 to 17.5 minutes. Compared with normozoospermia, the antioxidant potential is significantly lower (p = 0.05) in men with asthenozoospermia (about 1.4 times), and even lower in patients with asthenoteratozoospermia (about 1.7 times) (p = 0.03). An inverse weak correlation was found between the activity of leukocytes and latent time in pathospermia (r = –0.23 and –0.18 for asthenozoospermia и asthenoteratozoospermia, respectively). A direct strong correlation was found between ROS-producing sperm activity and latent time in normozoospermia (p = 0.79), and inverse correlation in pathospermia (r = –0.26 and –0.62 for asthenozoospermia и asthenoteratozoospermia, respectively).Conclusion. Pathospermia is characterized by antioxidant seminal plasma deficiency, more pronounced for asthenoteratozoospermia. The antioxidant system of seminal plasma correlates with the ROS-producing ability of leukocytes and, to a greater extent, of the sperm. With normozoospermia, the oxidative balance is maintained, with pathospermia, a higher value of ROS production by sperm corresponds to a lower value of antioxidant capacity.

The study objective is to compare of ejaculate parameters in mosaic, non-mosaic Klinefelter syndrome (KS).Materials and methods. Eighty-five patients with KS were examined. The group 1 included 75 patients between the ages of 17 and 39 with non-mosaic KS (47,XXY), the group 2 included 10 males between the ages of 22 and 57 years with mosaic KS: 47,XXY/46,XY (n = 9), 48,XXY,der(X)/47,XXY/46,XY (n = 1).Results. KS patients semen volume was 1.9 ± 1.3 (0.1–5.5) ml in non-mosaic KS patients (47,XXY) and 1.5 ± 1.2 (0.05–4.00) ml in patients with a mosaic form of a KS, respectively, рН semen – 7.8 ± 0.5 (6.5–9.0) and 7.8 ± 0.2 (7.5–8.1), sperm count – 0.27 ± 1.42 (0.00–12.50) and 0.12 ± 0.28 (0.00–0.90) million/ml, respectively. The viscosity was increased (>20 mm) at 41 % non-mosaic KS (group 1) and 22 % of mosaic KS (group 2) patients. The ejaculate sediment was investigated by quantitative karyological analysis of immature germ cells. The germ cells in 42 % samples of the ejaculate of the patients with a classical form of a KS and in 20 % samples of the ejaculate of the patients with a mosaic form was found. That indicates a partial preservation of spermatogenesis.Conclusion. The degree of spermatogenesis depletion in KS patients widely varied, ejaculate and germ cell parameters in the ejaculate sediment weren’t significantly different. Presence of few sperms (cryptozoospermia) and immature cells in the ejaculate sediment point to partial preservation of spermatogenesis.

The study objective is to compare the results of semen examination in patients with the congenital bilateral aplasia of vas deferens (CBAVD) syndrome and patients with cystic fibrosis.Materials and methods. Ninety-one patients with azoospermia were included in the study, 38 of them with CBAVD and 53 with cystic fibrosis. There were no significant differences in semen parameters (volume, viscosity and pH of the seminal fluid, the count of sperm and leukocytes) between the patients’ groups. In most samples of the ejaculate sediment, investigated by quantitative karyological analysis, spermatozoa and/or immature germ cells were found, indicating a partial preservation of patency of the vas deferens in most of CBAVD patients, also as azoospermic men with CF. Obtained data refute the generally accepted opinion about the absence of vas deferens in these patients, therefore, it is necessary to revise the terminology and further study the pathogenesis of abnormalities of vas deferens and seminal vesicles.

The study objective is to evaluate spermatogenesis using the method of quantitative karyological analysis of immature germ cells from the ejaculate sediment (QKAIGC) in patients with azoospermia or cryptozoospermia with normal and low semen volume.Materials and methods. Seventy-two (72) semen samples from patients with suspected azoospermia were analyzed, 48 with normal semen volume (≥1,5 ml) and 24 with low semen volume (

Rationale: Cystic fibrosis (CF) is a common hereditary disease related to the CFTR gene mutations and characterized by progression and multiple system involvement (primarily of the digestive tract and / or pulmonary system). Most men with CF are infertile. Due to new therapeutic options, the life expectancy of CF patients has increased, with reproductive issues becoming relevant.Aim: A multifaceted assessment of the reproductive system status and fertility in male patients with CF and improvement of the strategies to resolve their reproduction issues.Materials and methods: This cohort prospective study was performed 2006 to 2018 and included 81 unrelated Russian male patients with confirmed CF, aged from 15 to 69 years (mean age 25.6 ± 7.9 years). Forty two (42) patients had pancreatic sufficient and 39 pancreatic insufficient CF. The patients underwent clinical, andrological, laboratory and instrumental examination (scrotal ultrasonography, standard and biochemical semen examination and hormone levels).Results: Reproductive disorders and semen abnormalities found in CF patients varied from preserved fertility to infertility. The following andrological abnormalities were found: delayed puberty (48%), urological disorders (26%), uni- or bilateral testicular hypoplasia (42%), diffuse lesions and cysts of the epididymis (70%), diffuse lesions /calcifications of the prostate (50%), and decreased testosterone levels (24.2%). Azoospermia was diagnosed in 87.5% of the patients, “moderate” or “mild” pathozoospermia (oligo-/astheno-/teratozoospermia) in 11.1%, and normozoospermia in 1.4% of the patients. There were significant differences between the patients with pancreatic sufficient and pancreatic insufficient CF in the ejaculate volume (1.4 ± 1.5 ml vs. 0.6 ± 0.5 ml; р = 0.006), ejaculate pH (6.7 ± 0.7 vs. 6.1 ± 0.4; р < 0.0001), and sperm concentration (19.6 ± 56.0 Mio/mL vs. 0.001 ± 0.008 Mio/ mL; p = 0.011). Normal ejaculate volume was more frequent (21.1% vs 14.7%; p > 0.05) in patients under the age of 25. No bilateral obstruction of vas deferens was found in 71.4% patients with 3849+10kbC>T mutation. There was a significant difference (p < 0.00001) in the frequency of 3849+10kbC>T mutation between the patients with vas deferens obstruction (9.5%) and without it (93.8%). We developed an algorithm to resolve infertility issues (including assisted reproductive technologies) in male CF patients depending on their fertility / presence and type of pathozoospermia and some other factors that may influence the conception and CF risk in the offspring. We also suggested practical recommendations for the andrological assessment, maintenance of reproductive health, and planning of childbirth in these patients.Conclusion: Male CF patients require a multifaceted assessment of their reproductive system. The prognosis of their reproductive functions, the strategy to maintain their reproductive health and making a decision on childbirth depends on the CF type, the CFTR genotype, the results of semen analysis, and the patient’s age. Pancreatic sufficient CF type, 3849+10kbС>T mutation of the CFTR gene and younger age are favorable factors for potential maintenance of vas deferens patency and male fertility in CF patients.

Introduction. Cystic fibrosis (CF) is common monogenic disease resulted from CFTR gene mutations. A most of CF male patients are infertile due to the obstructive azoospermia, however, the mechanisms of the reduced fertility in male patients without the obstruction of seminal ducts, also as the influence of CFTR genotype on their development is understudied.Objective is to assess an influence the effect of CFTR genotype, clinical form of CF and age on men reproductive system organs, fertility, and testosterone level and semen parameters in male patients with CF. Materials and methods. We examined 71 Russian men (17–39 years old, mean 24.9 ± 5.3) with CF (pancreatic-sufficient, n = 34, and pancreatic-insufficient, n = 37). Clinical, andrology, laboratory and instrumental examination, including scrotal ultrasonography, biochemical semen, and hormonal analyses were performed.Results. Testicular hypoplasia was reveled in 40,5 % CF patients. Diffuse alterations of epididymis, of epididymal and/or testicular cysts were detected in 62 % patients; 10 % of the patients presented symptoms of hypogonadism. As many as 88 % patients showed spermiological signs of bilateral obstruction of seminal ducts at the level of the vas deferens and epididymis, aplasia of the seminal vesicles (azoospermia, oligospermia, low pH and fructose level of the ejaculate). Pancreatic-insufficient CF is an unfavorable prognostic sign for the obstruction of vas deferens, morphological changes in the scrotum. Patients until 25 years (23 %) as 3849+10kb C>T mutation’s carriers (72 %) significantly more frequently presented preserved vas deferens.Conclusion. Pancreatic-sufficient CF, young age and 3849+10kbС>T mutation are favorable factors presented preserved vas deferens and the possible fertility in men with CF.

Introduction. Cystic fibrosis (CF) is a common genetic disorder associated with male infertility. Almost all men with CF are infertile due to obstructive azoospermia.The objective is to evaluate semen parameters, excretion of seminal fluid, and spermatogenesis in CF patients.Materials and methods. We examined 44 male CF patients with pancreatic sufficiency (n = 20) and pancreatic insufficiency (n = 24). Standard semen analysis, quantitative karyological analysis of immature germ cells from ejaculate sediment, biochemical semen analysis (fructose, α-glucosidase, citric acid) were performed.Results. Semen analysis diagnosed azoospermia in 77.3 % patients, severe oligozoospermia (< 1 million/ml) and other diagnoses (oligozoospermia, asthenozoospermia, normozoospermia) in 13.6 % and 9.1 % patients, respectively. The signs of obstruction of the vas deferens and aplasia of seminal vesicles were observed in 91 % patients. Azoospermia, oligospermia, pH

We analyzed 755 semen samples from men with infertility in marriage and/or disorders of reproductive system. Standard semen analysis (WHO, 2010) was performed for all the samples. Only 11 % of the samples were normozoospermic. Various types of semen pathology were found in 89 % of the investigated samples. Necrozoospermia was detected in 1 % of the samples. Oligospermia was revealed in 12 % of the samples, in 98 % cases it was accompanied by pathozoospermia (abnormal morphology, low sperm concentration or motility). The most common types of pathozoospermia were asthenozoospermia (41 % of all studied samples), asthenoteratozoospermia (26 %) and oligoasthenoteratozoospermia (15 %). Azoospermia and cryptozoospermia were totally observed in 4 % of the samples. 3 % of the samples were defined as other types of pathozoospermia (teratozoospermia, oligozoospermia etc.). Positive correlations between the percentage of morphologically normal spermatozoa and the percentage of motile, percentage of progressively motile spermatozoa, concentration and total number of spermatozoa were found.

Male factor contributes significantly to the problem of infertile marriages. Alterations of morphological and/or functional characteristics of germ cells can result in infertility. We analyzed 122 semen samples – 55 samples with normal (≥ 15 million/ml) sperm concentration (group I) and 67 samples with cryptozoospermia or severe oligozoospermia (concentration < 1 million/ml, group II). Standard semen analysis and quantitative karyological analysis of immature germ cells from ejaculate (QKA IGC) (patent L.F. Kurilo № 2328736, 2007) were performed for all samples. The results of QKA IGC are significantly different in the two groups analyzed. The proportion of IGC at stages of preleptotene-zygotene and pachytene is verified to be higher (p < 0.01) in the sperm samples with normal concentration (group 1), indicating spermatogenesis arrest at prophase I of meiosis. In the semen samples of group 2 (patients with cryptozoospermia or with severe oligozoospermia, sperm concentration < 1 million/ml) proportion of spermatocytes II and spermatids is significantly higher than in the group with normal sperm concentration, that indicates the spermatogenesis arrest at the stage of sperm formation (spermiogenesis). IGC index in 58 % of the samples from the group I is higher than normal IGC index. For the majority of the samples from the group II the IGC index was not estimated because of lack of spermatozoa. In all sperm samples with suspected azoospermia examined through QKA IGC spermatozoa were identified (44 samples from group II). Thus, if azoospermia is suspected, QKA IGC can be recommended to patients as an alternative to diagnostic testicular or epididimal biopsy. QKA IGC is unique in the assessment of the of spermatogenesis dynamics, as it is precise, safe, non-invasive and time-saving method that allows multiple repeated evaluation of IGC at different stages of spermatogenesis.

Male germ cells pool forms due to proliferation of germ cells during migration into the embryonic gonads and apoptosis. At the different stages of antenatal development a part of germ сells population in the seminiferous cords is represented by cells at the preleptotene stage of meiosis I. In newborns and infants a number of gametes at this stage of meiosis varies. Male germ cells enter meiotic development mainly in the puberty period. One of the theories of the unique chromatin condensation at the preleptotene stage (prochromosome) is a lack of special signal molecules responsible for the male gametes development. Another theory is that it is a modification that marks the germ сells capable of meiosis activation.

Polyzoospermia is extremely high (above 250 mln/ml) sperm concentration with normal volume of ejaculate. In the laboratory of genetic disorders of reproduction of Research Centre for Medical Genetics in 2007–2012 years we analyzed more than 14 000 semen samples from infertile men and men with reproductive disorders in order to study the distribution and characteristics of spermatogenesis in polyzoospermic men. Only polyzoospermic men semen analysis results were interpretered in present article. Polyzoospermia (sperm count over 250 mln/ml in volume over 1,5 ml) was detected in 191 semen samples (1.3 %). At the same time 15 % of the samples with polyzoospermia were normozoospermic. Among 85 % of the sperm pathology samples asthenozoospermia occured most frequently (77 %), astenoteratozoospermia was detected in 8 % of cases with polyzoospermia. The average proportion of vitality was 90.09 ± 10.02 %, normal morphology – 14.93 ± 8.51 %, and progressive motility – 17.72 ± 11.81 %. The average concentration of spermatozoa in the ejaculate in the examined samples was 313.29 ± 64.78 mln/ml. More than half of the tested samples with polyzoospermia had a concentration 250–300 mln/ml. Concentration of 450 mln/ml and more detected in 3 % of samples. The maximum total number of spermatozoa in the ejaculate in our study was more than 2 billion sperm cells and was observed in two polyzoospermic men. One of these patients had the maximum concentration (615 mln/ml) also. We found a high correlation (r = 0.89; p < 0.01) between the volume of ejaculate and the total number of spermatozoa. Immature germ cells from ejaculate were estimated in 7 patients. There was a partial spermatogenesis arrest at meiosis I prophase in 5 out 7 of the examined semen samples.

Genetic and epigenetic mechanisms of spermatogenesis – long process with many stages regulation are discussed. DNA code is the entirety of hereditary information, epigenetic mechanisms of gene regulation act without altering primary nucleotide sequences. Epigenetic regulation is a complex process, in which components of different groups of epigenetic modifications (non-coding RNAs, DNA methylation and histone modification) work together. Mistakes in any of the components of the process may cause impaired spermatogenesis and/or infertility, and may cause epigenetic diseases. Nowadays 90 imprinted genes and loci on 13 chromosomes are revealed. More then 10 human diseases involving genomic imprinting are known (Angelman syndrome, Prader–Willi syndrome, Russell–Silver syndrome, Beckwith–Wiedemann syndrome etc.). DNA methylation is essential for normal development and is associated with a number of key processes including animal growth and development, transcription, DNA replication and reparation, cell differentiation, genomic imprinting, X-chromosome inactivation, suppression of repetitive elements and carcinogenesis.