136
views
0
recommends
+1 Recommend
0 collections
    5
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Effect of oxidative stress on male reproduction.

      Read this article at

          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Infertility affects approximately 15% of couples trying to conceive, and a male factor contributes to roughly half of these cases. Oxidative stress (OS) has been identified as one of the many mediators of male infertility by causing sperm dysfunction. OS is a state related to increased cellular damage triggered by oxygen and oxygen-derived free radicals known as reactive oxygen species (ROS). During this process, augmented production of ROS overwhelms the body's antioxidant defenses. While small amounts of ROS are required for normal sperm functioning, disproportionate levels can negatively impact the quality of spermatozoa and impair their overall fertilizing capacity. OS has been identified as an area of great attention because ROS and their metabolites can attack DNA, lipids, and proteins; alter enzymatic systems; produce irreparable alterations; cause cell death; and ultimately, lead to a decline in the semen parameters associated with male infertility. This review highlights the mechanisms of ROS production, the physiological and pathophysiological roles of ROS in relation to the male reproductive system, and recent advances in diagnostic methods; it also explores the benefits of using antioxidants in a clinical setting.

          Related collections

          Most cited references81

          • Record: found
          • Abstract: found
          • Article: not found

          Strategies of antioxidant defense.

          H Sies (1993)
          Cellular protection against the deleterious effects of reactive oxidants generated in aerobic metabolism, called oxidative stress, is organized at multiple levels. Defense strategies include three levels of protection; prevention, interception, and repair. Regulation of the antioxidant capacity includes the maintenance of adequate levels of antioxidant and the localization of antioxidant compounds and enzymes. Short-term and long-term adaptation and cell specialisation in these functions are new areas of interest. Control over the activity of prooxidant enzymes, such as NADPH oxidase and NO synthases, is crucial. Synthetic antioxidants mimic biological strategies.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            The role of sperm oxidative stress in male infertility and the significance of oral antioxidant therapy.

            Oxidative stress in the male germ line is thought to affect male fertility and impact upon normal embryonic development. Accordingly, fertility specialists are actively exploring the diagnosis of such stress in spermatozoa and evaluating the possible use of antioxidants to ameliorate this condition. In this review, evidence for the presence of oxidative stress in human spermatozoa, the origins of this phenomenon, its clinical significance in the aetiology of male infertility and recent advances in methods for its diagnosis and treatment are re-examined. Moreover, an extensive review of the results presented in published clinical studies has been conducted to evaluate the overall impact of oral antioxidants on measures of sperm oxidative stress and DNA damage. Administration of antioxidants to infertile men has been assessed in numerous clinical studies with at least 20 reports highlighting its effect on measures of oxidative stress in human spermatozoa. A qualitative but detailed review of the results revealed that 19 of the 20 studies conclusively showed a significant reduction relating to some measure of oxidative stress in these cells. Strong evidence also supports improved motility, particularly in asthenospermic patients. However, of these studies, only 10 reported pregnancy-related outcomes, with 6 reporting positive associations. Adequately powered, placebo-controlled comprehensive clinical trials are now required to establish a clear role for antioxidants in the prevention of oxidative stress in the male germ line, such that the clinical utility of this form of therapy becomes established once and for all.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Control of hyperactivation in sperm.

              Sperm hyperactivation is critical to fertilization, because it is required for penetration of the zona pellucida. Hyperactivation may also facilitate release of sperm from the oviductal storage reservoir and may propel sperm through mucus in the oviductal lumen and the matrix of the cumulus oophorus. Hyperactivation is characterized by high amplitude, asymmetrical flagellar bending. This is a review of the original literature on the mechanisms that regulate hyperactivation, including physiological factors and signaling pathways. Computer-assisted semen analysis systems can be used to identify hyperactivated sperm by setting minimum thresholds for curvilinear velocity (VSL) and lateral head movement and a maximum threshold for path linearity. Hyperactivation is triggered by a rise in flagellar Ca(2+) resulting from influx primarily through plasma membrane CatSper channels and possibly also by release of Ca(2+) from a store in the redundant nuclear envelope. It requires increased pH and ATP production. The physiological signals that trigger the rise in Ca(2+) remain elusive, but there is evidence that the increased Ca(2+) acts through a calmodulin/calmodulin kinase pathway. Hyperactivation is considered part of the capacitation process; however, the regulatory pathway that triggers hyperactivation can operate independently from that which prepares sperm to undergo the acrosome reaction. Hyperactivation may be modulated by chemotactic signals to turn sperm toward the oocyte. Little is known about exactly what triggers hyperactivation in human sperm. This information could enable clinicians to develop reliable fertility assays to assess normal hyperactivation in human sperm samples.
                Bookmark

                Author and article information

                Journal
                World J Mens Health
                The world journal of men's health
                Korean Society for Sexual Medicine and Andrology (KAMJE)
                2287-4208
                2287-4208
                Apr 2014
                : 32
                : 1
                Affiliations
                [1 ] Center for Reproductive Medicine, Cleveland Clinic, Cleveland, OH, USA.
                [2 ] Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, South Africa.
                Article
                10.5534/wjmh.2014.32.1.1
                4026229
                24872947
                c3198737-1d49-4b3f-9fef-2e63761aa421
                History

                Oxidative stress,Infertility, male,Reactive oxygen species,Antioxidants,Spermatozoa

                Comments

                Comment on this article