Recent studies have shown that shorter periods of ejaculatory abstinence may enhance certain sperm parameters, but the molecular mechanisms underlying these improvements are still unclear. This study explored whether reduced abstinence periods could improve semen quality, particularly for use in assisted reproductive technologies (ART). We analyzed semen samples from men with normal sperm counts ( n = 101) and those with low sperm motility or concentration ( n = 53) after 3-7 days of abstinence and then after 1-3 h of abstinence, obtained from the Reproductive & Genetic Hospital of CITIC-Xiangya (Changsha, China). Physiological and biochemical sperm parameters were evaluated, and the dynamics of transfer RNA (tRNA)-derived fragments (tRFs) were analyzed using deep RNA sequencing in five consecutive samples from men with normal sperm counts. Our results revealed significant improvement in sperm motility and a decrease in the DNA fragmentation index after the 1- to 3-h abstinence period. Additionally, we identified 245 differentially expressed tRFs, and the mitogen-activated protein kinase (MAPK) signaling pathway was the most enriched. Further investigations showed significant changes in tRF-Lys-TTT and its target gene mitogen-activated protein kinase kinase 2 ( MAP2K2 ), which indicates a role of tRFs in improving sperm function. These findings provide new insights into how shorter abstinence periods influence sperm quality and suggest that tRFs may serve as biomarkers for male fertility. This research highlights the potential for optimizing ART protocols and improving reproductive outcomes through molecular approaches that target sperm function.
Male ; Humans ; Spermatozoa/metabolism* ; RNA, Transfer/genetics* ; Sperm Motility/genetics* ; Adult ; Semen Analysis ; Sexual Abstinence/physiology* ; Sperm Count ; DNA Fragmentation

OBJECTIVE: To investigate the correlation of seminal plasma oxidation reduction potential (ORP), normalized oxidation-reduction potential (nORP) and sperm DNA fragmentation index (DFI) to sperm motion parameters, and their clinical predictive value for oligoasthenozoospermia (OAZ). METHODS: This study included 433 male subjects visiting the Clinic of Andrology in our hospital from March to May 2024. According to sperm concentration and the percentage of progressively motile sperm (PMS), we divided them into a normal control (n = 119), an oligozoospermia (OZ, n = 118), an athenozoospermia (AZ, n = 119) and an OAZ group (n = 77). Using the electrode method, we measured the seminal plasma ORP, calculated nORP=ORP/sperm concentration (mV/［10⁶/ml］), and determined DFI and high DNA chromatin sperm (HDS) by flow cytometry based on sperm chromatin structure assay (SCSA), followed by comparison among the four groups in age, abstinence days, semen volume, total sperm count, sperm concentration, PMS, non-progressively motile sperm (NPMS), immotile sperm (IMS), curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP), linearity (LIN), straightness(STR), wobble (WOB), DFI, HDS, ORP and nORP. Using the receiver operating characteristic (ROC) curve, we assessed the predictive value of DFI, ORP and nORP for OAZ, and analyzed the correlation of DFI, ORP and nORP to sperm motion parameters by Pearson and Spearman analyses. RESULTS: Statistical analysis revealed statistically significant differences among the four groups in semen volume, abstinence days, total sperm count, sperm concentration, PMS, NPMS, IMS, total sperm motility, VCL, VSL, VAP, STR, DFI, HDS, ORP and nORP (P < 0.05), but not in age, LIN and WOB (P > 0.05). The area under the ROC curve (AUC) for the predictive value of DFI for OAZ was 0.880, with the critical value of 8.920, sensitivity of 74.8% and specificity of 88.2%; that of ORP for AZ was 0.698, with the critical value of 155.375, sensitivity of 70.6% and specificity of 64.7%; and that of nORP for OZ was 0.999, with the critical value of 9.844, sensitivity of 98.3% and specificity of 99.2%. Pearson and Spearman correlation analyses showed that DFI was correlated positively with age, abstinence days, semen volume, IMS, HDS and ORP, but negatively with PMS, NPMS, total sperm motility, VCL, VSL, VAP and STR; ORP positively with abstinence days, semen volume, IMS, DFI and nORP, but negatively with PMS, NPMS, total sperm motility, VSL, LIN and STR; and nORP positively with HDS, but negatively with abstinence days, total sperm count, sperm concentration, PMS and NPMS. CONCLUSION Oxidative stress (OS) may be an important pathological factor for elevated ORP, increased DFI and changes of routine sperm motion parameters, consequently leading to OAZ. As OS markers, DFI and ORP have a high predictive value for OS-induced OAZ.
Male ; Humans ; DNA Fragmentation ; Semen/metabolism* ; Sperm Motility ; Spermatozoa ; Oxidation-Reduction ; Adult ; Oligospermia ; Sperm Count ; Semen Analysis ; Asthenozoospermia

This observational cohort study investigated the potential of a novel sperm-washing medium (SWM) enriched with serotonin (5-HT), L-carnitine (L-C), and coenzyme Q10 (CoQ10) to enhance sperm motility and reduce DNA damage. It compared this innovative medium (5-HT/L-C/CoQ10 SWM) with two widely used commercial media (SWM 1 and SWM 2). Ninety-eight volunteers from an infertility clinic provided semen samples, which were divided into three aliquots for analysis in different SWMs: group 1, SWM was composed of hydroxyethyl piperazineethanesulfonic acid (HEPES), sodium bicarbonate, human serum albumin (HSA), taurine, and gentamicin sulfate (SWM 1); group 2, SWM was composed of HEPES, sodium bicarbonate, and HSA (SWM 2); and group 3, SWM was composed of HEPES-buffered human tubal fluid supplemented with 5-HT, L-C, and CoQ10 (5-HT/L-C/CoQ10 SWM). Sperm motility was categorized as progressive, nonprogressive, or immotile. Apoptosis, reactive oxygen species (ROS) production, and DNA fragmentation were also assessed. There were no significant differences in total or progressive sperm motility among the groups. Spermatozoa in group 3 exhibited reduced apoptosis, necrosis, and ROS levels and increased viability. No significant differences were observed in the DNA fragmentation index among groups. The 5-HT/L-C/CoQ10 SWM reduced sperm oxidative stress and apoptosis compared with those of the two commercially available SWMs, suggesting that 5-HT/L-C/CoQ10 SWM could be useful for enhancing in vitro fertilization success rates.
Humans ; Male ; Serotonin ; Carnitine/pharmacology* ; Ubiquinone/pharmacology* ; Sperm Motility/drug effects* ; Adult ; Spermatozoa/drug effects* ; Cohort Studies ; Reactive Oxygen Species/metabolism* ; Culture Media ; DNA Fragmentation/drug effects* ; Apoptosis/drug effects* ; DNA Damage/drug effects*

To investigate the relationship between male semen parameters and sperm DNA fragment index with age. Adopt cross-sectional sampling survey design, 3 203 male patients who visited the Department of Reproductive Andrology in the Third Affiliated Hospital of Zhengzhou University from January 2019 to June 2021 were selected as subjects. Age range is 18-57 years, with the median age of 30 years. Through quartile regression analysis, the correlation between age and different male semen parameters and DNA fragment index (DFI) was presented. The study population was divided into ≤30 years old group and >30 years old group, and the correlation between age and semen volume, sperm concentration, total sperm count, progressive motility, total motility, percentage of normal sperm and DFI level were compared and analyzed. The results showed that there were significant differences in progressive motility, total motility and DFI level among different age groups (χ²=-4.608, -4.604, -7.719,P all <0.05), but there was no significant difference in semen volume, sperm concentration, total sperm count and percentage of normal sperm (χ²=-1.712, -1.203, -0.149, -0.175,P all >0.05). In the>30 years old age group, there was a very weak negative correlation between male age and semen volume, progressive motility and total motility (r=-0.137, -0.101 and -0.056, P all <0.05). There was a very weak positive correlation between male age and sperm concentration and sperm DFI level (r=0.061, 0.190, P all <0.05), while there was no correlation between male age and total sperm count and percentage of normal sperm (r=-0.018, -0.016,P all >0.05). In conclusion, with the increase of age, especially after the age of 30, semen volume, progressive motility and total motility decreased, while sperm concentration and DFI level increased, and semen quality decreased.
Humans ; Male ; Adult ; Adolescent ; Young Adult ; Middle Aged ; Semen ; Semen Analysis ; Cross-Sectional Studies ; Infertility, Male/genetics* ; Sperm Motility ; DNA Fragmentation ; Spermatozoa ; Sperm Count ; DNA

To investigate the relationship between male semen parameters and sperm DNA fragment index with age. Adopt cross-sectional sampling survey design, 3 203 male patients who visited the Department of Reproductive Andrology in the Third Affiliated Hospital of Zhengzhou University from January 2019 to June 2021 were selected as subjects. Age range is 18-57 years, with the median age of 30 years. Through quartile regression analysis, the correlation between age and different male semen parameters and DNA fragment index (DFI) was presented. The study population was divided into ≤30 years old group and >30 years old group, and the correlation between age and semen volume, sperm concentration, total sperm count, progressive motility, total motility, percentage of normal sperm and DFI level were compared and analyzed. The results showed that there were significant differences in progressive motility, total motility and DFI level among different age groups (χ²=-4.608, -4.604, -7.719,P all <0.05), but there was no significant difference in semen volume, sperm concentration, total sperm count and percentage of normal sperm (χ²=-1.712, -1.203, -0.149, -0.175,P all >0.05). In the>30 years old age group, there was a very weak negative correlation between male age and semen volume, progressive motility and total motility (r=-0.137, -0.101 and -0.056, P all <0.05). There was a very weak positive correlation between male age and sperm concentration and sperm DFI level (r=0.061, 0.190, P all <0.05), while there was no correlation between male age and total sperm count and percentage of normal sperm (r=-0.018, -0.016,P all >0.05). In conclusion, with the increase of age, especially after the age of 30, semen volume, progressive motility and total motility decreased, while sperm concentration and DFI level increased, and semen quality decreased.
Humans ; Male ; Adult ; Adolescent ; Young Adult ; Middle Aged ; Semen ; Semen Analysis ; Cross-Sectional Studies ; Infertility, Male/genetics* ; Sperm Motility ; DNA Fragmentation ; Spermatozoa ; Sperm Count ; DNA

We question whether, in men with an abnormal rate of sperm DNA fragmentation, the magnetic-activated cell sorting (MACS) could select spermatozoa with lower rates of DNA fragmentation as well as spermatozoa with unbalanced chromosome content. Cryopreserved spermatozoa from six males were separated into nonapoptotic and apoptotic populations. We determined the percentages of spermatozoa with (i) externalization of phosphatidylserine (EPS) by annexin V-Fluorescein isothiocyanate (FITC) labeling, (ii) DNA fragmentation by TdT-mediated-dUTP nick-end labeling (TUNEL), and (iii) numerical abnormalities for chromosomes X, Y, 13, 18, and 21 by fluorescence in situ hybridization (FISH), on the whole ejaculate and selected spermatozoa in the same patient. Compared to the nonapoptotic fraction, the apoptotic fraction statistically showed a higher number of spermatozoa with EPS, with DNA fragmentation, and with numerical chromosomal abnormalities. Compared to the whole ejaculate, we found a significant decrease in the percentage of spermatozoa with EPS and decrease tendencies of the DNA fragmentation rate and the sum of disomy levels in the nonapoptotic fraction. Conversely, we observed statistically significant higher rates of these three parameters in the apoptotic fraction. MACS may help to select spermatozoa with lower rates of DNA fragmentation and unbalanced chromosome content in men with abnormal rates of sperm DNA fragmentation.
Annexin A5 ; Chromosome Aberrations ; DNA Fragmentation ; Humans ; In Situ Hybridization, Fluorescence ; In Situ Nick-End Labeling ; Male ; Pilot Projects ; Semen ; Spermatozoa

Damage to sperm DNA was proposed to play an important role in embryonic development. Previous studies focused on outcomes after fresh embryo transfer, whereas this study investigated the influence of sperm DNA fragmentation index (DFI) on laboratory and clinical outcomes after frozen embryo transfer (FET). This retrospective study examined 381 couples using cleavage-stage FET. Sperm used for intracytoplasmic sperm injection (ICSI) or in vitro fertilization (IVF) underwent density gradient centrifugation and swim up processing. Sperm DFI had a negative correlation with sperm motility (r = -0.640, P < 0.01), sperm concentration (r = -0.289, P < 0.01), and fertilization rate of IVF cycles (r = -0.247, P < 0.01). Sperm DFI examined before and after density gradient centrifugation/swim up processing was markedly decreased after processing (17.1% vs 2.4%, P < 0.01; 65 randomly picked couples). Sperm progressive motility was significantly reduced in high DFI group compared with low DFI group for both IVF and ICSI (IVF: 46.9% ± 12.4% vs 38.5% ± 12.6%, respectively; ICSI: 37.6% ± 14.1% vs 22.3% ± 17.8%, respectively; both P < 0.01). The fertilization rate was significantly lower in high ( ≥25%) DFI group compared with low (<25%) DFI group using IVF (73.3% ± 23.9% vs 53.2% ± 33.6%, respectively; P < 0.01) but was equivalent in high and low DFI groups using ICSI. Embryonic development and clinical outcomes after FET were equivalent for low and high DFI groups using ICSI or IVF. In this study, sperm DFI did not provide sufficient information regarding embryo development or clinical outcomes for infertile couples using FET.
DNA Fragmentation ; Embryo Transfer ; Female ; Fertilization in Vitro ; Humans ; Male ; Pregnancy ; Retrospective Studies ; Sperm Motility ; Spermatozoa

Semen analysis has long been used to evaluate male fertility. Recently, several sperm function tests have been developed. Of those, the sperm DNA fragmentation index (DFI), which describes the status of the sperm DNA, is thought to be a suitable parameter for evaluating male fertility. However, there have been no large-scale studies on the sperm DFI of Japanese men. Therefore, we investigated the feasibility of using an in-house flow cytometry-based sperm DFI analysis based on the sperm DNA fragmentation test of sperm chromatin structure assay (SCSA) to assess male fertility in Japan. This study enrolled 743 infertile and 20 fertile Japanese men. To evaluate reproducibility, inter- and intraobserver precision was analyzed. A receiver operating characteristic curve analysis was used to set a cutoff value for the sperm DFI to identify men who could father children by timed intercourse or intrauterine insemination. The variability of the sperm DFI among fertile volunteers was determined. The relationship between semen parameters and the sperm DFI was assessed by Spearman's rho test. A precision analysis revealed good reproducibility of the sperm DFI. The cutoff value of sperm DNA fragmentation in infertile men was 24.0%. Semen volume had no relationship with the sperm DFI. Sperm concentration, sperm motility, total motile sperm count, and percentage of normal-shaped sperm were significantly and negatively correlated with the sperm DFI. The median sperm DFI was smaller in fertile volunteers (7.7%) than that in infertile men (19.4%). Sperm DNA fragmentation analysis can be used to assess sperm functions that cannot be evaluated by ordinary semen analysis.
Child ; Chromatin ; DNA Fragmentation ; Flow Cytometry ; Humans ; Infertility, Male/genetics* ; Japan ; Male ; Reproducibility of Results ; Sperm Motility ; Spermatozoa

The renin angiotensin system (RAS) appears to influence male fertility at multiple levels. In this work, we analyzed the relationship between the RAS and DNA integrity. Fifty male volunteers were divided into two groups (25 each): control (DNA fragmentation ≤20%) and pathological (DNA fragmentation >20%) cases. Activities of five peptidases controlling RAS were measured fluorometrically: prolyl endopeptidase (which converts angiotensin [A] I and A II to A 1-7), neutral endopeptidase (NEP/CD10: A I to A 1-7), aminopeptidase N (APN/CD13: A III to A IV), aminopeptidase A (A II to A III) and aminopeptidase B (A III to A IV). Angiotensin-converting enzyme (A I to A II), APN/CD13 and NEP/CD10 were also assessed by semiquantitative cytometry and quantitative flow cytometry assays, as were the receptors of all RAS components: A II receptor type 1 (AT1R), A II receptor type 2 (AT2R), A IV receptor (AT4R or insulin-regulated aminopeptidase [IRAP]), (pro)renin receptor (PRR) and A 1-7 receptor or Mas receptor (MasR) None of the enzymes that regulate levels of RAS components, except for APN/CD13 (decrease in fragmented cells), showed significant differences between both groups. Micrographs of RAS receptors revealed no significant differences in immunolabeling patterns between normozoospermic and fragmented cells. Labeling of AT1R (94.3% normozoospermic vs 84.1% fragmented), AT4R (96.2% vs 95.3%) and MasR (97.4% vs 87.2%) was similar between the groups. AT2R (87.4% normozoospermic vs 63.1% fragmented) and PRR (96.4% vs 48.2%) were higher in non-fragmented spermatozoa. These findings suggest that fragmented DNA spermatozoa have a lower capacity to respond to bioactive RAS peptides.
Angiotensins ; DNA Fragmentation ; Humans ; Insulin ; Male ; Renin-Angiotensin System/physiology* ; Spermatozoa

This study analyzed the effects of male age and abstinence time on semen quality and explored the best abstinence time for Chinese males among different age groups. Semen parameters, including sperm kinetics, morphology, and DNA fragmentation index (DFI), were reviewed from 2952 men. Samples were divided into six age groups (≤25 years, 26-30 years, 31-35 years, 36-40 years, 41-45 years, and >45 years) and were divided into six groups according to different abstinence time (2 days, 3 days, 4 days, 5 days, 6 days, and 7 days). The differences in semen quality between the groups were compared, and the effect of age and abstinence time on semen quality was analyzed. Significant differences were observed in semen volume, progressive motility (PR), and DFI among the age groups (all P < 0.05), and no significant differences were observed in sperm morphological parameters (all P > 0.05). There were significant differences in semen volume, PR, and DFI among different abstinence time groups (all P < 0.05) and no significant differences in sperm morphological parameters (all P > 0.05). Pearson analysis showed that male age and abstinence time were both significantly correlated with sperm kinetics and DFI (both P < 0.05), while no significant correlation was found with sperm morphological parameters (all P > 0.05). The box plots and histograms of men's age, abstinence time, and semen quality show that most semen quality parameters differ significantly between the 2 days and 7 days abstinence groups and other groups at different ages. Except for the sperm morphology parameters, sperm kinetic parameters and sperm DFI are linearly related to male age and abstinence time.
Adult ; DNA Fragmentation ; Humans ; Male ; Retrospective Studies ; Semen ; Semen Analysis ; Sperm Count ; Sperm Motility ; Spermatozoa