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

Abstract

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.

Sperm DNA integrity assays: diagnostic and prognostic challenges and implications in management of infertility

“…There are varied reports [116][117][118] on the efficiency of various antioxidant therapy in infertile men. Recent meta analysis [119,120] of these studies suggest that antioxidant therapy is beneficial and improves various indices of male fertility. However antioxidants should only be administered in cases with increased free radical levels as majority of enzymatic reactions in our body functions under redox conditions.…”

Olive Leaves Extract Improved Sperm Quality and Antioxidant Status in the Testis of Rat Exposed to Rotenone

“…The positive effects of dietary intake antioxidant on semen parameters were documented in several studies (38,39). Some authors reported that OLE possessed antioxidant property and increased diminished antioxidant enzyme activities in different tissue (40,41).…”

Synergism between the N-acetyltransferase 2 gene and oxidant exposure increases the risk of idiopathic male infertility

“…Oxidative stress is a wellknown mechanism of chemical-and/or carcinogen-induced tumours, resulting from an imbalance between the production of reactive oxygen species (ROS) and their efficient removal by available antioxidant defence systems (Valko et al, 2006). Notably, oxidative stress together with associated sperm DNA damage and apoptosis have been clearly implicated in the pathogenesis of idiopathic infertility in men (Agarwal and Said, 2005;Aitken et al, 2003;Gharagozloo and Aitken, 2011;Sanocka et al, 1997). Since oxidative stress is thought to be involved in the pathogenesis of idiopathic male infertility, polymorphisms of NAT2 may represent potential candidates for disease susceptibility.…”