Clinical relevance of oxidative stress and sperm chromatin damage in male infertility: an evidence based analysis

Abstract

Oxidative stress (OS) in the reproductive tract is now a real entity and concern due to the potential harmful effects of high levels of reactive oxygen species (ROS) on sperm number, motility, quality, and function including damage to sperm nuclear DNA. Evaluation of OS related damage to non-functional sperm is highly relevant as intracytoplasmic sperm injection (ICSI) technique, an effective therapy for severe male factor infertility, bypasses the majority of reproductive tract deficiencies. Despite the controversial findings in the existing literature, there is now enough evidence to show that sperm DNA damage is detrimental to reproductive outcomes. In addition, spermatozoa of infertile men are suggested to carry more DNA damage than do the spermatozoa from fertile men. Besides impairment of fertility such damage is likely to increase the transmission of genetic diseases during the assisted reproductive procedures. Standardization of protocols to assess reactive oxygen species and DNA damage is very important in introducing these tests in such clinical practice. Thus evaluation of seminal ROS levels and extent of sperm DNA damage especially in an infertile male may help develop new therapeutic strategies and improve success of assisted reproductive techniques (ART).

Relationship between reactive oxygen species production in human semen and sperm DNA damage assessed by Sperm Chromatin Structure Assay

“…Some authors have reported a positive correlation between ROS production and sperm DNA damage 18,19 . The results of our study demonstrated that there was a trend of rising DFI %, from control group to NSI group to infertile group with abnormal semen parameters.…”

Activity of antioxidant enzymes in seminal plasma and their relationship with lipid peroxidation of spermatozoa

“…Aerobic metabolism of human sperm produces various reactive oxygen species (ROS), which are potentially harmful to the sperm plasma membrane with its high content of polyunsaturated fatty acids (1)(2)(3). There is growing evidence that lipid peroxida�lini�al Urology �lini�al Urology tion damage to the plasma membrane of spermatozoa plays an important role in the mechanism of male infertility (4)(5)(6).…”

Effect of Seminal Transforming Growth Factorß1 (TGFß1) and Glutathione on Apoptosis in Spermatozoa from Tunisian Infertile Men

“…We can predict that the injection of these compromised spermatozoa may affect the outcome of assisted reproduction in multiple ways, including effects on the fertilization rates, embryo cleavage, and pregnancy rates. In addition, our data show that high level of seminal TGFß1 (>100 ng/ml) which is a critical semen parameter associated with infertility, is a predictive factor for an increased risk of sperm DNA damage [14][15][16][17].…”

“…Subjects currently on any medication or antioxidant supplementation were not included [16][17][18][19][20][21][22][23][24]. In addition, subjects with testicular varicocele, genital infection, leukocytespermia, chronic illness and serious systemic diseases, smokers and alcoholic men were excluded from the study because of their well-known high seminal ROS levels and decreased antioxidant activity.…”