Oxidative stress (OS) has been recognized as one of the most important cause of male infertility. Despite the antioxidant activity of seminal plasma, epididymis and spermatozoa, OS damages sperm function and DNA integrity. Since antioxidants suppress the action of reactive oxygen species, these compounds have been used in the medical treatment of male infertility or have been added to the culture medium during sperm separation techniques. Nevertheless, the efficacy of such a treatment has been reported to be very limited. This may relate to: (i) patient selection bias; (ii) late diagnosis of male infertility; (iii) lack of double-blind, placebo-controlled clinical trial; and/or (iv) use of end-points that are not good markers of the presence of OS. This review considers the effects of the main antioxidant compounds used in clinical practice. Overall, the data published suggest that no single antioxidant is able to enhance fertilizing capability in infertile men, whereas a combination of them seems to provide a better approach. Taking into account the pros and the cons of antioxidant treatment of male infertility, the potential advantages that it offers cannot be ignored. Therefore, antioxidant therapy should remain in the forefront of preventive medicine, including human reproductive medicine.
"From a practical point of view, these results underscore recommendations for the arrest of cigarette smoking and alcohol abuse and for encouraging the consumption of diets rich in fruits and vegetables as a means of male infertility prevention in reproduction medicine. Useful medical applications of these results can be also realized through the clinical evaluation of antioxidant therapy in infertile men to effectively manage sperm oxidative stress and ultimately to ameliorate this condition, as has been recommended (Lanzafame et al., 2009). From a research perspective, a pathwaybased approach where several genes for xenobioticmetabolizing and antioxidant defence enzymes are selected for analysis in combination with the knowledge of the chemical factor can represent a more comprehensive and fruitful strategy to identifying the joint effects and gene–environment interactions underlying male infertility. "
[Show abstract][Hide abstract] ABSTRACT: N-acetyltransferase (NAT2) is a phase-II xenobiotic-metabolizing enzyme participating in the detoxification of toxic arylamines, aromatic amines and hydrazines. The present study was designed to investigate whether two common single-nucleotide polymorphisms (SNP) of the NAT2 gene (481C>T, rs1799929; 590G>A, rs1799930) are associated with susceptibility to idiopathic male infertility and to assess if the risk is modified by oxidant and antioxidant exposures. A total 430 DNA samples (203 infertile patients and 227 fertile men) were genotyped for the polymorphisms by PCR and restriction fragment length polymorphism. No association was found between the NAT2 polymorphisms and idiopathic male infertility. However, gene–environment interaction analysis revealed that a low-acetylation genotype, 590GA, was significantly associated with increased disease risk in men who had environmental risk factors such as cigarette smoking (OR 1.71, 95% CI 1.02–2.87, P = 0.042), alcohol abuse (OR 2.14, 95% CI 1.08–4.27, P = 0.029) and low fruit/vegetable intake (OR 1.68, 95% CI 1.01–2.79, P = 0.04). This pilot study found, as far as is known for the first time, that the polymorphism 590G>A of NAT2 is a novel genetic marker for susceptibility to idiopathic male infertility, but the risk is potentiated by exposure to various environmental oxidants.
"Oxidation stress occurs when the production of reactive oxygen species (ROS) exceeds the antioxidant-scavenging capacity of a cell or tissue. The link between oxidation stress and male infertility has received substantial scientific support (Agarwal et al., 2008a; Gharagozloo and Aitken, 2011; Lanzafame et al., 2009); indeed, excessive ROS production negatively impacts sperm quality and function due to the induction of detrimental chemical and structural modifications to sperm DNA and membrane lipids (Benedetti et al., 2012; Khosrowbeygi and Zarghami, 2007; Shiva et al., 2011). The involvement of free radicals in female infertility is less well known and controversial. "
[Show abstract][Hide abstract] ABSTRACT: Ovarian stimulation is used with IVF/intracytoplasmic sperm injection (ICSI) cycles to obtain multiple oocytes and improve pregnancy rates; however, it also induces perturbation in the oxidant–antioxidant balance leading to oxidation stress. The present study monitored the plasma antioxidant status in women undergoing a long agonist protocol of ovarian stimulation at three different time points: at baseline (T0), after pituitary suppression (T1) and on the day of oocyte retrieval (T2). The antioxidant composition of follicular fluid samples collected on T2 was also evaluated. Significant decreases (P < 0.05) of plasma vitamin C, vitamin E and carotenoids were found between T1 and T2 but not between T0 and T1. At T2, high plasma vitamin E was associated with high numbers of total and mature oocytes retrieved per patient, which, in turn, were favourable for achieving pregnancy. Accordingly, women who became pregnant presented higher vitamin E concentrations both in plasma and FF than those who did not. In conclusion, this study confirmed the occurrence of significant modifications of the plasma antioxidant profile during ovarian stimulation with gonadotrophins; at the same time, it was found that both systemic and follicular antioxidant status may be related to IVF/ICSI outcome.
"High seminal ROS levels lead to oxidative stress that in turn can reduce sperm quality and increase sperm DNA fragmentation rates –. The susceptibility of sperm cells to oxidative stress is partly due to their limited antioxidant machinery and high metabolic activity , –. In addition, oxidative stress stimulates a lipid peroxidation cascade in the plasma membrane that in particular influences sperm motility –. "
[Show abstract][Hide abstract] ABSTRACT: Background
Following the Chernobyl nuclear power plant accident, large amounts of radionuclides were emitted and spread in the environment. Animals living in such contaminated areas are predicted to suffer fitness costs including reductions in the quality and quantity of gametes.
We studied whether aspermy and sperm quality were affected by radioactive contamination by examining ejaculates from wild caught birds breeding in areas varying in background radiation level by more than three orders of magnitude around Chernobyl, Ukraine. The frequency of males with aspermy increased logarithmically with radiation level. While 18.4% of males from contaminated areas had no sperm that was only the case for 3.0% of males from uncontaminated control areas. Furthermore, there were negative relationships between sperm quality as reflected by reduced sperm velocity and motility, respectively, and radiation.
Our results suggest that radioactive contamination around Chernobyl affects sperm production and quality. We are the first to report an interspecific difference in sperm quality in relation to radioactive contamination.
PLoS ONE 06/2014; 9(6):e100296. DOI:10.1371/journal.pone.0100296 · 3.23 Impact Factor
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