A comparison of ejaculated and testicular spermatozoa aneuploidy rates in patients with high sperm DNA damage

Testicular spermatozoa are utilized to achieve pregnancy in couples with severe male factor infertility. Several studies suggest that aneuploidy rates in spermatozoa are elevated at the testicular level in infertile patients compared to ejaculates of normal controls. However, essential data regarding aneuploidy rates between ejaculated and testicular spermatozoa in the same individuals is lacking. The purpose of our study was to compare aneuploidy rates at the testicular and post-testicular level from the same patients with persistently high sperm DNA damage. Ejaculates and testicular biopsies were obtained from eight patients with persistently high DNA damage (>30%). Both ejaculated and testicular samples were analyzed for sperm DNA damage and sperm aneuploidy for chromosomes 13, 18, 21, X, and Y. In addition, semen samples from ten normozoospermic men presenting for fertility evaluation served as a control group. A strong correlation between the alteration of spermatogenesis and chromatin deterioration was observed in our study. In the same individuals, testicular samples showed a significantly lower DNA damage compared to ejaculated spermatozoa (14.9%?± 5.0 vs. 40.6%?± 14.8, P<0.05), but significantly higher aneuploidy rates for the five analyzed chromosomes (12.41%?± 3.7 vs. 5.77%?± 1.2, P<0.05). While testicular spermatozoa appear favourable for ICSI in terms of lower DNA damage, this potential advantage could be offset by the higher aneuploidy rates in testicular spermatozoa.     

DNA fragmentation status in patients with necrozoospermia

The aim of this study was to determine if a relationship exists between the levels of sperm DNA fragmentation and necrospermia in infertile men. Semen samples obtained from 70 men consulting for infertility evaluation were analyzed according to World Health Organization (WHO) guidelines. Patients were subdivided into three groups according to the percentage of necrotic spermatozoa: normozoospermia (<30%; n?=?20), moderate necrozoospermia (50-80%; n?=?30), and severe necrozoospermia (>80%; n?=?20). DNA fragmentation was detected by the terminal desoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick-end labeling (TUNEL) assay. The sperm DNA fragmentation index (DFI) was 9.28?±?2.98% in patients with a normal level of necrotic spermatozoa, 20.25?±?3.21% in patients with moderate necrozoospermia, and 35.31?±?5.25% in patients with severe necrozoospermia. There was a statistically significant increase of DNA fragmentation in the necrozoospermic group (P?<?0.01). A strong correlation was found between the degree of necrozoospermia and sperm DNA fragmentation. We concluded that patients with necrozoospermia showed a high level of DNA fragmentation compared to normozoospermic men. Severe necrozoospermia (>80%) is a predictive factor for increased sperm DNA damage.     

Meiotic segregation study of a novel t(3;6)(q21;q23) in an infertile man using fluorescence in situ hybridization (FISH)

Male carriers with balanced reciprocal translocations can produce a variable proportion of unbalanced gametes resulting in reproductive failures. The presence of a structural rearrangement may induce an interchromosomal effect. This is characterized by abnormal bivalents not involved in the reorganization thereby yielding non-disjunction, which would present as aneuploid spermatozoa for these chromosomes. In the present case report segregation analysis of the sperm and investigation of interchromosomal effect were carried out using cytogenetic and fluorescence in situ hybridization (FISH) analysis on blood lymphocytes. The karyotype of the patient was 46,XY,t(3;6)(q21;q23). During sperm segregation analysis a total of 2,002 sperms were evaluated, of which 46.8% showed normal/balanced (alternate segregation mode) and 53.2% of sperm showed an abnormal signal pattern. A significant difference in the frequency of the estimated number of chromosome anomalies was observed in the translocation carrier when compared to the normozoospermic group (P?<?0.0001) and the oligozoospermic group (P?<?0.0001). Meiotic segregation analysis of sperm together with aneuploidy assessment for X, Y, and 17 chromosomes using FISH allows for the determination of a reproductive prognosis in male balanced translocation carriers and can be used for appropriate genetic counseling.     

Disruption of Telomere–Telomere Interactions Associated with DNA Damage in Human Spermatozoa

Telomeres play a fundamental role in the organization of the sperm nucleus resulting in the looped chromosome configuration and non-random positioning of chromosomes. Telomeres localize in the nuclear periphery and interact dynamically by forming dimers and tetramers. The purpose of this study was to evaluate the relationship of telomere interactions to DNA damage, a factor known to adversely influence male fertility.

Telomeres were localized by fluorescence in situ hybridization (FISH) using human chromosome pan-telomeric probe in ten samples with low and ten samples with high sperm DNA damage. The samples with a low DNA fragmentation index (DFI) had a mean number of telomere signals of 21.7±1.9 compared to a mean of 26.5±3.4 signals in the samples with a high DFI (p<.005). The percentage of cells with a typical telomere distribution of ≤23 telomere-telomere dimers was observed in 70.8%±15.6 samples with a low DFI compared to 44.2%±22.4 in samples with a high DFI (p<.05).

These results suggest that sperm DNA damage is associated with disruption of the normal telomere–telomere interactions leading to possible loss of the looped chromosome configuration. Improperly packed and organized sperm chromatin might have a high probability of disrupting the extremely structured sequence of sperm chromosome deposition, activation, and processing by the oocyte at the time of fertilization. These results might provide additional information on the nature of sperm DNA damage and the role of such damage on fertilization and development of the zygote.     

SPERM CHROMOSOME ANEUPLOIDY AS RELATED TO MALE FACTOR INFERTILITY AND SOME ULTRASTRUCTURE DEFECTS

Some men have elevated levels of sperm chromosome aneuploidy. In this study, we have evaluated and summarized sperm aneuploidy rates in male infertility patients and control groups. The mean aneuploidy rate for five chromosomes (X, Y, 13, 18, 21) was 1.2 ± 0.1 for fertile controls, 1.4 ± 0.1 for a general population control group, and 5.8 ± 1.14 for the patients. When the patients were classified by the type of male factor infertility, the total aneuploidy rate was 2.6 ± 0.3 in men with moderately diminished semen quality (n = 7), 4.0 ± 0.3 patients with severe teratoasthenooligozoospermia, and 15.9 ± 3.8 for men with rare ultrastructure defects such as round head only syndrome or severe tail agenesis. Some infertility patients have a severely elevated level of sperm chromosome aneuploidy, which may contribute to infertility or diminish the likelihood of a successful outcome from IVF/ICSI. The severity of sperm chromosome aneuploidy appears to be proportional to the severity of abnormal semen quality: in particular, abnormal morphology. The high rates of aneuploidy in patients with severe ultrastructure defects suggest that caution should be employed in counseling those patients prior to IVF/ICSI.     

Comparative analysis of antioxidants against cadmium induced reproductive toxicity in adult male rats

Abstract

The present study was conducted to compare and evaluate the potential benefits of three different antioxidants in reversing cadmium (Cd)-induced reproductive toxicity in adult male rats. Rats (n?=?5) weighing 180?±?20?gm were divided into five groups (control, Cd, Cd?+?sulforaphane, Cd?+?vitamin E, and Cd?+?plant extract). Treated groups received CdCl₂ (0.2?mg/kg), sulforaphane (25?µg/rat), vitamin E (75?mg/kg), and plant extract (100?mg/kg) for 15 days. Blood samples and testicular tissues were obtained for estimation of testosterone, Zn, and Cd concentration and daily sperm production/efficiency of sperm production. Cadmium exposure caused a significant decrease in final body weight (p?<?0.0001). The plasma concentrations of Cd were significantly increased and Zn concentration decreased (p?<?0.0001) in the Cd group as compared to the control group. The testicular concentrations of Cd were significantly increased and Zn concentration decreased (p?<?0.0001) in the Cd group as compared to the control group. Cadmium exposure caused a significant decrease (p?<?0.0001) in plasma testosterone concentrations and daily sperm production as compared to the control group. More significant effects were observed with Cd+sulforaphane, Cd?+?vitamin E, and Cd?+?plant extract treated groups in slashing Cd-induced toxicity. Present findings suggest that Ficus religiosa and sulforaphane are more powerful antioxidants as compared to vitamin E in reversing the oxidative stress and can have a protective role against Cd induced reproductive toxicity in adult male rats. Part of the mechanism involved in this protective role seems to be associated with the antioxidant properties of these agents in reducing reproductive damage.     

Porcine embryos produced after intracytoplasmic sperm injection using xenogeneic pig sperm from neonatal testis tissue grafted in mice

Embryo development after homologous intracytoplasmic sperm injection (ICSI) with sperm from testis tissue xenografts from pigs or any other farm animal species has not been evaluated critically. Here, we report development of porcine embryos in vitro following ICSI with sperm retrieved from xenografted neonatal pig testis. Small pieces of testis tissue from newborn piglets were grafted under the back skin of castrated immunodeficient mice (n = 4) and the xenografts were collected 8 months after grafting. Spermatozoa were recovered by mincing of the grafted tissue. For comparison, testicular, epididymal and ejaculated spermatozoa were also collected from mature boars. Oocytes injected with xenogeneic spermatozoa were either fixed to determine fertilisation processes (n = 89 in five replicates) or allowed to develop in vitro (n = 143 in four replicates). Xenogeneic porcine spermatozoa were fertilisation competent (24% v. 58%, 68%, 62% or 0% for xenogeneic v. control testicular, epididymal and ejaculated spermatozoa or no spermatozoa, respectively) and embryos developed to the blastocyst stage (8% v. 22%, 27%, 25% or 0%, respectively). These results demonstrate that porcine spermatozoa derived from immature testis tissue xenografted into mice are fertilisation competent, albeit at a lower rate than testicular, epididymal or ejaculated spermatozoa from control boars, and support embryo development after ICSI.     

Analysis of sperm nuclear protein gene polymorphisms and DNA integrity in infertile men

Sperm nuclear proteins, the protamines (PRM) and transition nuclear proteins (TNP) play a crucial role in sperm nuclear condensation. The compact packaging of sperm DNA by protamines maintains sperm genome integrity, which is prerequisite for normal sperm function. However the effect of nucleotide variations in PRM and TNP genes on sperm DNA integrity and male fertility is not clear. This case-control study was planned to analyze PRM and TNP gene nucleotide variations and sperm DNA integrity in 100 oligozoospermic infertile men and 100 fertile controls. Protamine and TNP genes were amplified by polymerase chain reaction and sequenced. Flow cytometry-sperm chromatin structure assay (FC-SCSA) was applied to measure the DNA fragmentation index (DFI) in sperm. Semen analysis was performed as per WHO [1999] guidelines with slight modification. In total, 7 nucleotide variations including two novel changes, a non-synonymous mutation in the exon-2 of PRM2 gene (c.443C?>?A) and a novel insertion of T (c.396_397InsT) at the 3′ UTR region of TNP1 were detected. None of the nucleotide changes were observed with increased risk frequency in the oligozoospermic infertile men compared to the controls. Though overall DFI was significantly (p?<?0.0001) higher in infertile men compared to controls (36.31?±?7.25 vs. 26.49?±?2.78) irrespective of nucleotide changes, no such difference was observed between 100 infertile men or pooled population of 200 with and without mutations. However it was observed that two cases with novel nucleotide changes PRM2 c.443C?>?A and TNP1 c.396_397InsT had higher DFI value of 34.82% and 43.85%, respectively. In conclusion, our pilot study for the first time in the Indian population revealed two rare novel mutations in sperm nuclear protein genes that are perhaps associated with higher sperm DNA fragmentation.     

LESS NO PRODUCTION AND BETTER MOTION PARAMETER IN HUMAN SPERM BY SWIM-UP PROCESSING

Fifteen semen specimens were obtained from men for semen analysis; each was divided into two aliquots for prepararation. The motile sperm recovery rate, percentage motility, and motion parameters were measured for each semen specimen (n?=?15) before and after preparation with the use of the two methods, and cultured with different time courses (1?hr, 3?hr, and 6?hr). Nitric oxide (NO) was measured using the chemiluminscence method after centrifugation. Recovery rate of motile cell was significantly higher in direct swim-up method (69.5?±?42.4% versus 49.3?±?29.3%, p?<?0.05). In motility, direct swim-up method in the different time courses was significantly better than IxaPrep method. (1?hr: 91.1?±?5.2% vs 65.6?±?16.4%, 3?hr: 87.2?±?7.9% vs 65.2?±?16.5%, 6?hr: 86.1?±?7.5% vs 60.8?±?17.6% and prewash: 61.6?±?16.2%, p?<?0.05). In VAP and VSL, the sperm prepared by the above two methods all improved compared to pre-wash sperm (p?<?0.05), but there was no statistical significance between the two methods. NO production in the direct swim-up group was significantly lower than IxaPrep group in the first hour of culture (0.09?±?0.09?uM vs 0.15?±?0.09?uM, p?<?0.05). NO production increased as the culture time increased in swim-up group, but conversed in IxaPrep group. The lower level of NO produced in the swim-up group may suggest that better sperm quality achieved is due to the decreased NO production.     

New method to estimate the possibility of natural pregnancy using computer-assisted sperm analysis

The World Health Organization (WHO) criteria, which include percent motility and sperm concentration, are the only criteria for evaluating sperm quality and conception ability. However, these criteria are insufficient to evaluate the possibility of natural pregnancy. Thus, an index that can directly evaluate the possibility of a natural pregnancy is necessary. A new sperm energy theory without approximation was developed to assess the possibility of natural pregnancy based on mechanical sperm energy. Sperm motility parameters were measured using computer-assisted sperm analysis (CASA) in 129 ejaculated semen samples from 50 men in couples diagnosed with infertility, in which no abnormalities were found in women (sterile group), and 157 ejaculated semen samples from 57 men who had already fathered children in natural pregnancies (control group). A total of 129 subjects were selected from the control group and classified as the fertile group in order of the sample measurement date. The sperm energy index (SEI) and mean sperm energy index (MEI) were accurately obtained according to the methods described by the new sperm energy theory. SEI reflects total mechanical energy of the sperm in a visual field during CASA measurements. MEI reflects the mean mechanical energy of one sperm in a measurement field. All subjects with (MEI)/(SEI)?>?2 were assigned to the sterile group. The larger the SEI, the higher was the probability of predicting fertile subjects. The probability of predicting fertile subjects was approximately 60% with a SEI of?>?0.5, 70% with a SEI of?>?1, 80% with a SEI of?>?3, and 90% with a SEI of?>?6 in cases where (MEI)/(SEI) is?<?2. The data support the view that this novel method can be used to estimate the possibility of a natural pregnancy.     

Does sperm DNA fragmentation affect the developmental potential and the incidence of apoptosis following blastomere biopsy?

Common methods employed in assisted reproduction technology (ART) include intracytoplasmic sperm injection (ICSI) with an unspecified level of sperm DNA fragmentation (SDF) and preimplantation genetic diagnosis (PGD). The aim of this study was to investigate the impact of SDF on human preimplantation embryo development and the incidence of apoptosis following a single blastomere biopsy. Using sperm chromatin dispersion (SCD) to assess SDF, a total of 20 processed semen samples were categorized into two groups; group I: SDF ≤30% and group II: SDF >30%. After ICSI, fertilization, cleavage, and embryo quality score were assessed. A single blastomere was biopsied from day 3 embryos and development was monitored on day 4. The frequency of apoptosis in biopsied embryos was assayed by TUNEL and the level of BCL-2, BAX, hsa-mir-15a, and hsa-mir-16-1 were assessed by quantitative real-time polymerase chain reaction (qRT-PCR). SCD was found to be negatively correlated with sperm motility and normal form spermatozoa (p?<?0.05). The rate of fertilization, cleavage, and embryo quality score were not significantly different between the two groups (all p?>?0.05). SDF >30% had no negative effect on potential development and did not increase the proportion of apoptotic cells and the level of apoptosis-related genes and microRNAs (miRNAs) in group II vs. group I (p?>?0.05). It appears that at the levels assessed paternal genome damage had little if any negative effect on preimplantaton embryo development and apoptosis following single blastomere biopsy. This may reflect the selection of morphologically normal sperm for ICSI and the repair capacity of the oocyte.     

Effect of testicular spermatozoa on embryo quality and pregnancy in patients with non-obstructive azoospermia

Abstract

This study was performed to assess and compare the outcomes of testicular sperm extraction (TESE)-intracytoplasmic sperm injection (ICSI) using spermatozoa from fresh and frozen testicular tissue from men with subgroups of non-obstructive azoospermia (NOA). A total of 110 cycles of TESE-ICSI were performed. Patients were classified into one of the following NOA subgroups: hypospermatogenesis (HS), maturation arrest (MA), or Sertoli cell-only syndrome (SCO). Laboratory (fertilization, cleavage stage of embryo, and good quality embryo) and clinical (pregnancy, clinical pregnancy, implantation, and delivery) outcomes were assessed. No statistically significant differences were observed in any of the other measured parameters between the three subgroups of NOA. No significant differences in laboratory outcomes were observed between spermatozoa from fresh and frozen testicular spermatozoa; however, statistically significant differences were observed in the pregnancy and implantation rates between groups (p?<?0.05). The outcomes of using spermatozoa retrieved from fresh testicular tissue in each of the three subgroups were also compared; although clinical outcomes showed low results, no significant differences were observed between the three subgroups. Similarly, no significant differences were observed in spermatozoa retrieved from frozen testicular tissue. Once spermatozoa have been successfully obtained, acceptable laboratory outcomes can be achieved for NOA, whether or not the spermatozoa are cryopreserved. However, satisfactory clinical outcomes may be more difficult to achieve as the results showed in each group of fresh and frozen testicular spermatozoa. Therefore, achieving acceptable clinical pregnancy results and efficient cryopreservation of testicular spermatozoa should be considered in patients with NOA.     

Sperm DNA damage correlates with polycyclic aromatic hydrocarbons biomarker in coke-oven workers

Objectives: The aim was to determine whether occupational exposure to polycyclic aromatic hydrocarbons (PAHs) in men has adverse effect on semen quality. Methods: Forty-eight coke-oven workers, including 16 topside-oven (TO) workers and 32 sideoven (SO) workers, were studied. Ambient PAHs exposure, urinary 1-hydroxypyrene (1-OHP) levels, and parameters of semen quality were determined. Results: TO workers had significantly higher ambient PAHs exposure (3,436.1±3,411.0 vs. 1,123.1±1,829.3 ng/m³, P<0.01), urinary 1-OHP levels (207.8±176.4 vs. 54.0±44.8 μg/g, P<0.001), frequency of oligospermia (18.8 vs. 0%, P<0.05), and morphological abnormality in sperm (32.3 vs. 14.6%, P<0.01) than SO workers. Among cigarette smokers, TO workers had significantly higher rates of DNA denaturation in spermatozoa (αT) and percentage of sperm with increased DNA denaturation (COMP αT) levels than SO workers (246.2±49.5 vs. 198.1±30.3 for αT; 34.8±14.4 vs. 19.3±13.9% for COMP αT, P<0.05). There was a positive correlation between urinary 1-OHP and αT, COMP αT, and abnormal sperm morphology and a tenfold increase in urinary 1-OHP associated with a 2.35-fold increase in αT, as well as a 1.07-fold increase in percentage of sperm with abnormal morphology. Conclusions: A potential risk of sperm dysfunction should be considered for workers occupationally exposed to high levels of PAHs. Cigarette smoking may aggravate this risk. Urinary 1-OHP can be used as a biomarker predicting sperm dysfunction.     

Relationship of seminal plasma antioxidants and serum male hormones with sperm chromatin status in male factor infertility

We explored the relationship between sperm chromatin integrity, hormone levels, seminal plasma total antioxidant capacity (TAC), and routine sperm parameters in men with male factor (MF, n?=?81) and non-male factor (NMF, n?=?52) infertility. Semen and blood were collected and examined from men undergoing evaluation for infertility in the Avicenna Infertility Clinic. We have examined each patient for serum hormones (LH, FSH, E2, DHEA), sperm chromatin damage, level of protamination and seminal plasma TAC. Levels of FSH, LH, sperm chromatin damage, and abnormal protamination were significantly higher in MF vs. NMF groups (p?<?0.001). Sperm chromatin damage was correlated with percentage of CMA₃- positive sperm (r?=?0.64, p?<?0.001) and with sperm concentration (r?=??0.36, p?<?0.001), motility (r?=??0.21, p?<?0.05), and morphologically normal spermatozoa (r?=??0.29, p?<?0.001). Linear regression showed sperm chromatin damage was related to percentage of CMA₃- positive sperm (p?<?0.001) in ungrouped patients. It was related to both percentage of CMA₃- positive sperm and serum DHEA in the MF group (p?<?0.001 and p?<?0.05, respectively). Sperm chromatin maturity assessed by CMA₃ test was inversely related to sperm chromatin damage assessed by the toludine blue assay. Male factor infertility associated with sperm chromatin damage may be related to sperm protamination and to serum DHEA.     

Anterior positioning of sex chromosomes on the head of human sperm sorted using visible wavelengths

The human ejaculate contains subpopulations of sperm with distinct properties. Human X- and Y-bearing sperm were separated with fluorescence activated cell sorting. To avoid the use of UV light the quantitative DNA dyes DRAQ5® and Dyecycle? Vybrant® Violet were used. Sorting efficiency was similar for both dyes, but lower than what is usually obtained with the classical method involving Hoechst 33342 and UV light (60-70% enrichment, versus 80-90%). A total of 2,739 spermatozoa were evaluated, from seven distinct samples using fluorescence in situ hybridization (FISH) chromosomal probes. No differences were found in sorted and unsorted populations in terms of chromosome positioning, and numeric chromosomal anomalies were not more evident following cell sorting. Furthermore in both sorted and unsorted populations the sex chromosomes were clearly located in the anterior portion of the sperm head, while a control autosome (chromosome 18) showed no such tendency, confirming previous findings. These results suggest that other quantitative DNA dyes may be used for sex chromosome-based human sperm sorting, but with lower efficiency than the standard UV-Hoechst based assay.     

COMPUTERIZED SEMEN ANALYSIS (CASA): EFFECT OF SEMEN CONCENTRATION AND CHAMBER DEPTH ON MEASUREMENTS

The gender of the offspring is determined by the fertilizing sperm. Previous gender studies were based on washed sperm, but not on sperm in seminal plasma. The objective was to correlate motility parameters assessed during semen analyses with the offspring gender. For comparison, fixed sperm head DNA quantitated by Hoechst 33342 fluorescence microscopy was also analyzed. Forty-six patients undergoing assisted reproduction procedures resulted in livebirth deliveries with either male or female-predominant offsprings. Sperm head fluorescence was weakly correlated to the gender in 61% of the cases. Sperm of patients with male offsprings had slower curvilinear (44.2?±?1.8 mean?±?SEM, versus, 49.9?±?2.7?µ/sec) and slower average path velocities (32.4?±?1.2 versus 36.3±1.7?µ/sec). Using cut-off values for the curvilinear (<49?µ/sec) and average path (<36?µ/sec) velocities of sperm swimming in seminal plasma, the two parameters predicted 75 and 68% of the male offspring births, respectively. The data suggest that sperm movement in seminal plasma is a marker for factors that skew the ratio of the X- to Y-sperm populations.     

DHR123: an alternative probe for assessment of ROS in human spermatozoa

The aim of this study was to assess the potential of dihydrorhodamine 123 (DHR123) to measure oxidative stress produced by human spermatozoa. The results were compared with 2', 7'-dichlorodihydrofluorescein diacetate (DCFH-DA) that is routinely used for assessment of H₂O₂ produced by spermatozoa. Fluorescence intensity and percentage R123 and DCF positive sperm were measured by flow cytometry. The optimal condition for assessment of reactive oxygen species (ROS) produced by sperm with DHR123 was 0.05 µM for 1 million sperm per ml for 20 minutes. The results of ROS measurement by DHR123 showed a significant correlation (r?=?+0.818, P?<?0.001) with DCFH-DA staining. Immunofluorescence of sperm stained with DHR123 revealed ROS production in the sperm mid-piece. In addition a significant correlation was observed between oxidant production assessed by DHR123 and semen parameters. Therefore, DHR123 may be considered a suitable probe for estimating oxidants produced by human spermatozoa, and can present heterogeneity in oxidant production between different samples.     

The three-dimensional image analysis of the chromocenter in motile and immotile human sperm

Chromosomes in human spermatozoa are arranged non-randomly with the centromeres of non-homologous chromosomes forming a chromocenter. We have compared motile and immotile sperm populations in normozoospermic patients to determine if there is any dissimilarity in the formation of the chromocenter and the nuclear position of chromosome 17. Based on the differences between motile and immotile populations, we propose for the ‘optimal’ nuclear organization to be defined as containing 1 to 3 chromocenter(s) with central radial and median longitudinal position for the centromere of chromosome 17. By this definition, 42% of motile spermatozoa had ‘optima’ nuclei, in comparison to 25% of immotile spermatozoa (P?<?0.05). Immotile spermatozoa exhibited a greater disruption in the formation of the chromocenter, altered position of the centromere of chromosome 17, and were more prone to chemical decondensation, resulting in higher nuclear and chromocenter volumes. The altered topology of the chromosomes might lead to the disruption of the sequence of events involved in fertilization and early embryonic development.     

Could zinc prevent reproductive alterations caused by cigarette smoke in male rats?

The aim of the present study was to evaluate the effects of zinc on fertility through semen parameters, testosterone level and oxidative DNA damage to spermatozoa of rats exposed to cigarette smoke. Male Wistar rats (60 days old) were divided into four groups (n = 10 per group): control, cigarette-smoking (20 cigarettes per day), zinc (zinc chloride 20 mg kg?1 day?1) and zinc plus cigarette-smoking (zinc chloride 20 mg kg?1 day?1; 20 cigarettes per day). The treatment was applied for nine weeks and the following parameters were analysed: bodyweight, wet weights of the reproductive organs and the adrenal gland, plasma testosterone concentration, testicular function (seminal analysis and daily sperm production) and sperm DNA oxidative damage. The exposure to cigarette smoke decreased testosterone concentration, the percentage of normal morphology and the motility of spermatozoa. In addition, this exposure increased sperm DNA oxidative damage. Zinc treatment protected against the toxic damage that smoking caused to spermatozoa. This study showed a correlation between smoking and possible male infertility and subfertility, and also that the majority of smoking-induced changes in spermatozoa were prevented by zinc treatment. In conclusion, zinc, an antioxidant and stimulant of cell division, can be indicated as a promising treatment in men with infertility caused by the toxic components of cigarette smoke.