Melatonin ameliorates restraint stress-induced oxidative stress and apoptosis in testicular cells via NF-κB/iNOS and Nrf2/ HO-1 signaling pathway.
Sci Rep. 2017 Aug 29;7(1):9599
Authors: Guo Y, Sun J, Li T, Zhang Q, Bu S, Wang Q, Lai D
Decline in semen quality has become a global public health concern. Psychological stress is common in the current modern society and is associated with semen decline. Increasing evidence demonstrated that melatonin has anti-apoptotic and antioxidant functions. Whether melatonin can ameliorate the damage in testes induced by psychological stress has never been investigated. Here, a mouse model of restraint stress demonstrated that melatonin normalized the sperm density decline, testicular cells apoptosis, and testicular oxidative stress in stressed male mice. Melatonin decreased reactive oxygen species (ROS) level, increased superoxide dismutase (SOD) and glutathione (GSH) activities, and downregulated inducible nitric oxide synthase (iNOS) and tumor necrosis factor-α (TNF-α) activities in stressed mice testes. Furthermore, melatonin reduced the stress-induced activation of the NF-κB signaling pathway by decreasing the phosphorylation of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα) and p65 nuclear translocation. In addition, melatonin upregulated the expression of anti-oxidant proteins including nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). Meanwhile, in vitro studies also demonstrated melatonin could reduce oxidative apoptosis of testicular cells. Collectively, melatonin mitigated psychological stress-induced spermatogenic damage, which provides evidence for melatonin as a therapy against sperm impairment associated with psychological stress.
PMID: 28851995 [PubMed - in process]
Identification and analysis of mtDNA genomes attributed to Finns reveal long-stagnant demographic trends obscured in the total diversity.
Sci Rep. 2017 Jul 21;7(1):6193
Authors: Översti S, Onkamo P, Stoljarova M, Budowle B, Sajantila A, Palo JU
In Europe, modern mitochondrial diversity is relatively homogeneous and suggests an ubiquitous rapid population growth since the Neolithic revolution. Similar patterns also have been observed in mitochondrial control region data in Finland, which contrasts with the distinctive autosomal and Y-chromosomal diversity among Finns. A different picture emerges from the 843 whole mitochondrial genomes from modern Finns analyzed here. Up to one third of the subhaplogroups can be considered as Finn-characteristic, i.e. rather common in Finland but virtually absent or rare elsewhere in Europe. Bayesian phylogenetic analyses suggest that most of these attributed Finnish lineages date back to around 3,000-5,000 years, coinciding with the arrival of Corded Ware culture and agriculture into Finland. Bayesian estimation of past effective population sizes reveals two differing demographic histories: 1) the 'local' Finnish mtDNA haplotypes yielding small and dwindling size estimates for most of the past; and 2) the 'immigrant' haplotypes showing growth typical of most European populations. The results based on the local diversity are more in line with that known about Finns from other studies, e.g., Y-chromosome analyses and archaeology findings. The mitochondrial gene pool thus may contain signals of local population history that cannot be readily deduced from the total diversity.
PMID: 28733587 [PubMed - in process]
MALDI-TOF MS as a Novel Tool for the Estimation of Postmortem Interval in Liver Tissue Samples.
Sci Rep. 2017 Jul 07;7(1):4887
Authors: Li C, Li Z, Tuo Y, Ma D, Shi Y, Zhang Q, Zhuo X, Deng K, Chen Y, Wang Z, Huang P
Estimation of the postmortem interval (PMI) is a complicated task in forensic medicine, especially during homicide and unwitnessed death investigations. Many biological, chemical, and physical indicators can be used to determine the postmortem interval, but most are not accurate. Here, we present a novel matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) method that can be used for the estimation of PMI using molecular images and multivariate analyses. In this study, we demonstrate that both rat and human liver tissues of various PMIs (0, 2, 4, and 6days) can be discriminated using MALDI imaging and principal component analysis (PCA). Using genetic algorithm (GA), supervised neural network (SNN), and quick classifier (QC) methods, we built 6 classification models, which showed high recognition capability and good cross-validation. The histological changes in all the samples at different time points were also consistent with the changes seen in MALDI imaging. Our work suggests that MALDI-TOF MS, along with multivariate analysis, can be used to determine intermediate PMIs.
PMID: 28687792 [PubMed - in process]
Estimation of postmortem interval by vitreous potassium evaluation with a novel fluorescence aptasensor.
Sci Rep. 2017 May 12;7(1):1868
Authors: Ding Y, Li X, Guo Y, Duan W, Ling J, Zha L, Yan J, Zou Y, Cai J
Estimation of postmortem interval (PMI) is a central role in medico-legal identification. Analysis of vitreous potassium ions (K(+)) concentration is frequently used by forensic workers to estimate PMI. This paper describes interdisciplinary research to introduce fluorescence sensing techniques into forensic medicine. On the basis of silver nanoclusters (AgNCs) probe stabilized by DNA, a simple and highly sensitive fluorescence aptasensor has been proposed to selectively detect K(+) ions. The linear range for K(+) ions was found to be 0.1 nM-1 mM, with limit of detection of 0.06 nM. Moreover, 63 vitreous humour cases within 36 h after death were further studied to verify the utility of K(+) ions in estimating the PMI. By the fluorescence aptasensor method, a new formula was built to determine the postmortem interval based on K(+) ions concentration: PMI(h) = -0.55 + 1.66 × CK(+)(r = 0.791). And the real significance of this research was demonstrated by additional 6 cases with known PMIs. In comparison with the conventional method, the presented aptasensor strategy is cost-effective and easy in measuring vitreous K(+), which may be potentially a better way for estimation of PMI in medico-legal practice.
PMID: 28500353 [PubMed - in process]
Chlamydia trachomatis neither exerts deleterious effects on spermatozoa nor impairs male fertility.
Sci Rep. 2017 Apr 25;7(1):1126
Authors: Puerta Suarez J, Sanchez LR, Salazar FC, Saka HA, Molina R, Tissera A, Rivero VE, Cardona Maya WD, Motrich RD
Chlamydia trachomatis is the most prevalent sexually transmitted bacterial infection. However, whether Chlamydia trachomatis has a negative impact on sperm quality and male fertility is still controversial. Herein, we report the effects on sperm quality of the in vitro exposure of spermatozoa to Chlamydia trachomatis, and also the effects of male genital infection on male fertility using an animal model. Human and mouse sperm were obtained from healthy donors and cauda epididimys from C57BL/6 mice, respectively. Highly motile human or mouse spermatozoa were in vitro exposed to C. trachomatis (serovar E or LGV) or C. muridarum, respectively. Then, sperm quality parameters were analyzed. Moreover, male fertility of Chlamydia muridarum infected male C57BL/6 mice was assessed. Human or murine sperm in vitro exposed to increasing bacterial concentrations or soluble factors from C. trachomatis or C. muridarum, respectively, did not show differences in sperm motility and viability, apoptosis, mitochondrial membrane potential, DNA fragmentation, ROS production and lipid peroxidation levels, when compared with control sperm (p > 0.05). Moreover, no differences in fertility parameters (potency, fecundity, fertility index, pre- and post-implantation loss) were observed between control and infected males. In conclusion, our results indicate that Chlamydia spp. neither directly exerts deleterious effects on spermatozoa nor impairs male fertility.
PMID: 28442719 [PubMed - in process]
Insights into the molecular basis of long-term storage and survival of sperm in the honeybee (Apis mellifera).
Sci Rep. 2017 Jan 16;7:40236
Authors: Paynter E, Millar AH, Welch M, Baer-Imhoof B, Cao D, Baer B
Honeybee males produce ejaculates consisting of large numbers of high quality sperm. Because queens never re-mate after a single mating episode early in life, sperm are stored in a specialised organ for years but the proximate mechanisms underlying this key physiological adaptation are unknown. We quantified energy metabolism in honeybee sperm and show that the glycolytic metabolite glyceraldehyde-3-phosphate (GA3P) is a key substrate for honeybee sperm survival and energy production. This reliance on non-aerobic energy metabolism in stored sperm was further supported by our findings of very low levels of oxygen inside the spermatheca. Expression of GA3P dehydrogenase (GAPDH), the enzyme involved in catabolism of GA3P, was significantly higher in stored compared to ejaculated sperm. Therefore, long-term sperm storage seems facilitated by the maintenance of non-aerobic energy production, the need for only the ATP-producing steps of glycolysis and by avoiding sperm damage resulting from ROS production. We also confirm that honeybee sperm is capable of aerobic metabolism, which predominates in ejaculated sperm while they compete for access to the spermatheca, but is suppressed during storage. Consequently, the remarkable reproductive traits of honeybees are proximately achieved by differential usage of energy production pathways to maximise competitiveness and minimise damage of sperm.
PMID: 28091518 [PubMed - in process]
Semen preparation methods and sperm telomere length: density gradient centrifugation versus the swim up procedure.
Sci Rep. 2016 Dec 13;6:39051
Authors: Zhao F, Yang Q, Shi S, Luo X, Sun Y
Previous studies have shown that both density gradient centrifugation (DGC) and swim up (SU) procedures can select spermatozoa with longer telomeres for assisted reproduction techniques (ART). However, it is unknown which approach is more effective. The aim of the present study was to compare the effects of these two methods on sperm telomere length (STL). A total of 150 normozoospermic subjects were recruited. STL, DNA fragmentation index (DFI), reactive oxygen species (ROS) content and progressive motility of semen samples were detected before and after the procedures of DGC and SU. When compared to raw semen, the average length of sperm telomeres was significantly longer after the two sperm preparation methods. However, no significant difference was found between the DGC and SU procedures. We also found that semen prepared by the two methods had lower DNA fragmentation, ROS content and sperm progressive motility. However, no significant difference was found in those parameters between the two procedures. This is the first study that compares the effects of the DGC and SU procedures on STL, and the results show that both methods can recover a sperm population with longer STL and better DNA integrity for ART.
PMID: 27958357 [PubMed - in process]
Hydrogen Sulfide and/or Ammonia Reduces Spermatozoa Motility through AMPK/AKT Related Pathways.
Sci Rep. 2016 Nov 24;6:37884
Authors: Zhao Y, Zhang WD, Liu XQ, Zhang PF, Hao YN, Li L, Chen L, Shen W, Tang XF, Min LJ, Meng QS, Wang SK, Yi B, Zhang HF
A number of emerging studies suggest that air pollutants such as hydrogen sulfide (H2S) and ammonia (NH3) may cause a decline in spermatozoa motility. The impact and underlying mechanisms are currently unknown. Boar spermatozoa (in vitro) and peripubertal male mice (in vivo) were exposed to H2S and/or NH3 to evaluate the impact on spermatozoa motility. Na2S and/or NH4Cl reduced the motility of boar spermatozoa in vitro. Na2S and/or NH4Cl disrupted multiple signaling pathways including decreasing Na(+)/K(+) ATPase activity and protein kinase B (AKT) levels, activating Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and phosphatase and tensin homolog deleted on chromosome ten (PTEN), and increasing reactive oxygen species (ROS) to diminish boar spermatozoa motility. The increase in ROS might have activated PTEN, which in turn diminished AKT activation. The ATP deficiency (indicated by reduction in Na(+)/K(+) ATPase activity), transforming growth factor (TGFβ) activated kinase-1 (TAK1) activation, and AKT deactivation stimulated AMPK, which caused a decline in boar spermatozoa motility. Simultaneously, the deactivation of AKT might play some role in the reduction of boar spermatozoa motility. Furthermore, Na2S and/or NH4Cl declined the motility of mouse spermatozoa without affecting mouse body weight gain in vivo. Findings of the present study suggest that H2S and/or NH3 are adversely associated with spermatozoa motility.
PMID: 27883089 [PubMed - in process]
Reproductive toxicity and gender differences induced by cadmium telluride quantum dots in an invertebrate model organism.
Sci Rep. 2016;6:34182
Authors: Yan SQ, Xing R, Zhou YF, Li KL, Su YY, Qiu JF, Zhang YH, Zhang KQ, He Y, Lu XP, Xu SQ
Sexual glands are key sites affected by nanotoxicity, but there is no sensitive assay for measuring reproductive toxicity in animals. The aim of this study was to investigate the toxic effects of cadmium telluride quantum dots (CdTe-QDs) on gonads in a model organism, Bombyx mori. After dorsal vein injection of 0.32 nmol of CdTe-QDs per individual, the QDs passed through the outer membranes of gonads via the generation of ROS in the membranes of spermatocysts and ovarioles, as well as internal germ cells, thereby inducing early germ cell death or malformations via complex mechanisms related to apoptosis and autophagy through mitochondrial and lysosomal pathways. Histological observations of the gonads and quantitative analyses of germ cell development showed that the reproductive toxicity was characterized by obvious male sensitivity. Exposure to QDs in the early stage of males had severe adverse effects on the quantity and quality of sperm, which was the main reason for the occurrence of unfertilized eggs. Ala- or Gly-conjugated QDs could reduce the nanotoxicity of CdTe-QDs during germ cell development and fertilization of their offspring. The results demonstrate that males are preferable models for evaluating the reproductive toxicity of QDs in combined in vivo/in vitro investigations.
PMID: 27669995 [PubMed - as supplied by publisher]
Effect of paternal overweight or obesity on IVF treatment outcomes and the possible mechanisms involved.
Sci Rep. 2016;6:29787
Authors: Yang Q, Zhao F, Hu L, Bai R, Zhang N, Yao G, Sun Y
Leukocyte telomere lengths (LTLs) are shorter in obese compared with normal weight people. However, it is not known whether sperm telomere length (STL) is related to obesity. The aim of the study was to evaluate the impact of men's body mass index (BMI) on STL, embryo quality, and clinical outcomes in couples undergoing IVF. In total, 651 couples were recruited, including 345 men with a normal BMI and 306 men with an overweight BMI (normal BMI group: 20-25 kg/m(2); overweight BMI group: >28 kg/m(2)). We found that couples with male's BMI over 28 kg/m(2) exhibited a significantly lower fertilization rate, good-quality embryo rate and clinical pregnancy rate compared to their normal BMI counterparts. The mean STL in the overweight BMI group was also significantly shorter than that of the normal BMI group. The results also showed that individuals with higher BMI had higher ROS (Reactive oxygen species) content and sperm DNA fragmentation rate when compared with normal BMI individuals. Mitochondrial activity was also lower in the overweight BMI group than in the normal BMI group. This is the first report to find that STL is shorter in overweight/obese men, which may account for their poorer treatment outcomes in IVF cycles.
PMID: 27412918 [PubMed - in process]