Simultaneous vitality and DNA-fragmentation measurement in spermatozoa of smokers and non-smokers

Effect of hubble-bubble smoking on global DNA methylation and transcription levels of protamine and histone genes in human spermatozoa

This study was conducted to assess the impact of hubble-bubble smoking on global DNA methylation, DNA fragmentation; protamine deficiency of spermatozoa, and to determine whether the transcription levels of the protamine and histone genes are different in hubble-bubble smokers compared to nonsmokers. Five hundred semen samples were collected from males with an average age of 32.2 ± 6.1 years (300 hubble-bubble smokers "60%" and 200 nonsmokers "40%"). The nucleic acid was isolated from purified sperm, then ELISA and qPCR were used to evaluate the global DNA methylation and transcription level of protamine and histone, respectively. A significant elevation in global DNA methylation, protamine deficiency, and DNA fragmentation was found in hubble-bubble smokers compared to nonsmokers (P < 0.0001). A significant decline was shown in transcription levels of protamine and histone genes in hubble-bubble compared to nonsmokers (P < 0.0001). Additionally, a down-regulation in the transcription levels of protamine and histone was revealed in hubble-bubble compared to nonsmokers with fold change (0.0001 and 0.007, respectively). In conclusion, this study provided proof that hubble-bubble smoking has a negative impact on global DNA methylation, DNA fragmentation, protamine deficiency, and the transcription of protamine and histone genes in spermatozoa, and these findings influence negatively males' fecundity.

Effect and mechanisms of reproductive tract infection on oxidative stress parameters, sperm DNA fragmentation, and semen quality in infertile males

Recent years have seen a rising incidence of male infertility, mostly caused by the decline of sperm quality. The ratio of infertile males to infertile females has escalated from 3:7 in 2013 to current 5:5, which turns male infertility into the research focus of reproductive medicine. This study aimed to clarify the effect of reproductive tract infection by ureaplasma urealyticum (UU) and chlamydia trachomatis (CT) on the DNA integrity and routine semen parameters of infertile males. A retrospective study was performed. A total of 259 infertile males who were treated at the Andrological Laboratory Examination and Reproductive Medicine Center in our hospital were analyzed. qRT-PCR was used to examine the infection status of CT and UU. According to the eligibility criteria, we evaluated the semen parameters and biochemical data of 253 men. Based on the results of PCR, the subjects were divided into four groups: Group I (CT positive, 63 cases), Group II (UU positive, 60 cases), Group III (CT positive and UU positive, 62 cases), and Group IV (no infection, 68 cases). DNA fragmentation index (DFI), sperm count, vitality and morphology, elastase level, seminal plasma malondialdehyde (MDA), and total antioxidant capacity (TAC) were assessed. Compared to Group IV, three groups (Group I, Group II and Group III) showed difference in semen volume, proportion of sperm with normal morphology, sperm motility, progressive motility, and vitality (P < 0.05). Compared to Group IV, Group II and Group III showed difference in DFI (P < 0.05). Compared to Group IV, Group II and Group III showed difference in elastase level (P < 0.05). VCL, VSL, VAP, WOB, ROS, TM, HDS showed differences between groups of abnormal/normal WBC (*P < 0.01).UU infection significantly increased the level of seminal leukocytes only in Group II, but not in the other three groups, indicating that UU is a factor to increase the level of seminal leukocytes. Compared with the normal leukocyte group, there were significant differences in total motility, forward motility and normal sperm ratio between the two groups. The proportion of sperm with abnormal morphology (mostly in the head) showed obvious difference between groups of high and normal seminal leukocytic levels. At the same time, in this study, SCGE and SCD verified that leukocytes could damage sperm DNA by increasing ROS, which ultimately affects male fertility.

Relationship between periodontal disease and male infertility: A case-control study

OBJECTIVES

To compare the prevalence of chronic periodontitis between men who had semen abnormalities and those who had normozoospermia through a case-control study.

MATERIALS AND METHODS

Male patients who visited the assisted reproduction clinic of a large general hospital and were diagnosed with semen abnormalities were included in the case group. The control group was composed of patients of the same clinic with normozoospermia. The semen analysis included sperm concentration, count and progressive and total motility, which were measured in the laboratory. A questionnaire and clinical periodontal examination were conducted for all participants. Logistic regression was performed to explore the relationship between chronic periodontitis and male infertility.

RESULTS

A total of 192 participants were included: 63 participants (32.8%) had some type of semen abnormality (case group), while 129 participants (67.2%) had normozoospermia (control group). The case group had a significantly higher prevalence of moderate/severe periodontitis than the control group (33.3% vs. 17.8%, p = .012). The logistic regression showed that participants who had moderate/severe periodontitis had a greater chance of having semen abnormalities after adjusting for other confounding factors (OR = 3.377, p = .005).

CONCLUSIONS

Periodontitis is associated with semen abnormalities and sperm motility in men.

Progress in Research on Sperm DNA Fragmentation

With the increasing incidence of male infertility, routine detection of semen is insufficient to accurately assess male fertility. Infertile men, who have lower odds of conceiving naturally, exhibit high levels of sperm DNA fragmentation (SDF). The mechanisms driving SDF include abnormal spermatogenesis, oxidative stress damage, and abnormal sperm apoptosis. As these factors can induce SDF and subsequent radical changes leading to male infertility, detection of the extent of SDF has become an efficient routine method for semen analysis. Although it is still debated, SDF detection has become a research hotspot in the field of reproductive medicine as a more accurate indicator for assessing sperm quality and male fertility. SDF may be involved in male infertility, reproductive assisted outcomes, and growth and development of offspring. The effective detection methods of SDF are sperm chromatin structure analysis (SCSA), terminal transferase-mediated dUTP end labeling (TUNEL) assay, single-cell gel electrophoresis (SCGE) assay, and sperm chromatin dispersion (SCD) test, and all of these methods are valuable for assisted reproductive techniques. Currently, the preferred method for detecting sperm DNA integrity is SCSA. However, the regulation network of SDF is very complex because the sperm DNA differs from the somatic cell DNA with its unique structure. A multitude of molecular factors, including coding genes, non-coding genes, or methylated DNA, participate in the complex physiological regulation activities associated with SDF. Studying SDF occurrence and the underlying mechanisms may effectively improve its clinical treatments. This review aimed to outline the research status of SDF mechanism and detection technology-related issues, as well as the effect of increased SDF rate, aiming to provide a basis for clinical male infertility diagnosis and treatment.

Semen quality and cigarette smoking in a cohort of healthy fertile men

BACKGROUND

Numerous health effects of smoking are well-known; associations with semen quality are uncertain. Most previous studies did not adjust for potential confounders and had limited information on age at smoking initiation or smoking cessation.

METHODS

We investigated 1,631 healthy fertile men in the Nanjing Medical University Longitudinal Investigation of Fertility and the Environment (NMU-LIFE) study. Relationships were examined using multivariable linear regression controlling for potential covariates.

RESULTS

We found a significant decrease in semen volume (β = -0.10, P = 0.001) and total sperm count (β = -0.42, P = 0.037), and significant increase in total motility (β = 6.02, P = 0.037) and progressive motility (β = 5.52, P = 0.037) in ever smokers of pack-years ≥10 compared with never smokers. We observed an inverse dose-dependent relation between smoking pack-years and semen volume (P < 0.001) and total sperm count (P = 0.010) and a positive dose-dependent relation between smoking pack-years and both total motility and progressive motility (P = 0.042 and 0.048, respectively). No significant differences in semen quality were detected among ever smokers with different ages at smoking initiation nor in former smokers compared with never smokers.

CONCLUSIONS

Cigarette smoking was associated with lower semen volume and total sperm count and higher sperm motility. Smoking cessation might have a restorative effect on semen quality. This finding has important implications for public health research and for understanding the development of abnormal semen quality.