Jannatifar R, Parivar K, Roodbari NH, Nasr-Esfahani MH. Effects of N-acetyl-cysteine supplementation on sperm quality, chromatin integrity and level of oxidative stress in infertile men. Reprod Biol Endocrinol. 2019;17(24).
To determine the impact of supplementation with the antioxidant N-acetyl-cysteine (NAC) on sperm quality, chromatin integrity, and level of oxidative stress in infertile men with abnormal seminal parameters
Three-month prospective, randomized, blinded, clinical trial
Fifty men, aged 25 to 40 years, with asthenoteratozoospermia as determined by WHO criteria. Participants reported no prior impregnations and had female partners without fertility issues.
Subjects with conditions and/or risk factors known to impair fertility (hormonal abnormalities, Klinefelter’s syndrome, varicocele, cryptorchidism, vasectomy, leukospermia, sperm antibodies, anatomical disorders, cancer, abnormal liver function, cigarette smoking, alcohol consumption, fever within 90 days of semen analysis) were excluded.
All participants received 600 mg oral NAC supplementation daily for 3 months.
Study Parameters Assessed
Semen analysis was used to assess the following seminal parameters: volume, sperm concentration, total motility, progressive motility, non-progressive motility, immotile sperm, and abnormal morphology. Other recorded data included DNA fragmentation index, levels of protamine deficiency, total antioxidant capacity (TAC), seminal malondialdehyde (MDA) levels, and hormonal parameters including serum levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and prolactin. Assessments were performed at baseline and at 3 months.
Primary Outcome Measures
Findings at 3 months were compared to those at baseline.
After 3 months of NAC, significant improvements were noted in all the seminal parameters evaluated: volume (P=0.01), sperm concentration (P=0.02), total motility (P=0.01), progressive motility (P=0.001), non-progressive motility (P=0.01), immotile sperm (P=0.01), and abnormal morphology (P=0.001).
There were also significant reductions in the percentages of DNA fragmentation (P=0.001) and protamine-deficient sperm (P=0.009). Levels of oxidative stress improved from baseline, as shown by a decrease in MDA (P=0.01) and an increase in TAC (P=0.01). All hormonal parameters except prolactin showed statistically significant differences, with decreases in FSH (P=0.01) and LH (P=0.04) and an increase in testosterone (P=0.01).
Male-factor infertility accounts for a significant percentage of infertility cases, with a prevalence approximately equivalent to that of female-factor infertility.1 Several etiologies have been identified, including congenital anomalies, genetic inheritance, poor lifestyle, environmental exposures, and iatrogenic conditions. If no cause is identifiable, a diagnosis of unexplained or idiopathic infertility is given.2 While the terms “unexplained” and “idiopathic” are often used synonymously, there is an important distinction. Patients with true unexplained infertility present with a normal workup, including semen analysis. In contrast, those with idiopathic infertility present with a normal workup, except for suboptimal semen analysis findings.3 The participants in this study were classified as the latter, since poor motility and morphology were detected (asthenoteratozoospermia).
After 3 months of NAC, significant improvements were noted in all of the seminal parameters evaluated.
Idiopathic male infertility is a current topic of interest among researchers, with specific focus on the association between oxidative stress and abnormal seminal parameters. Oxidative stress occurs when there is an excess of reactive oxygen species (ROS) with insufficient antioxidant stores.4 Under normal physiological conditions, spermatozoa produce small amounts of ROS, which are necessary for prefertilization events (sperm hyperactivation, capacitation, acrosome reaction).5 When present in excess, ROS impair spermatogenesis and threaten overall sperm quality.6 Male idiopathic infertility commonly presents with aberrations in both ROS and antioxidants, suggesting that these individuals bear a greater burden of oxidative stress.4,7
In the present study, malondialdehyde (MDA) and total antioxidant capacity (TAC) served as biomarkers of oxidative stress. MDA is produced when ROS initiate lipid peroxidation of polyunsaturated fatty acids (PUFAs). Because plasma membranes of spermatozoa contain PUFAs, seminal MDA levels serve as an indicator of lipid peroxidation.8 Several studies have demonstrated higher levels of MDA in infertile males, compared to those who are fertile.9,10 These findings suggest that seminal lipid peroxidation and subsequent oxidative stress contribute to the seminal abnormalities associated with idiopathic male infertility.
While the mechanism by which oxidative stress alters normal sperm physiology is unknown, recent research has revealed that it affects DNA integrity. The DNA fragmentation index and protamine content are considered to be promising markers of DNA damage. They appear to predict fertility outcomes better than a semen analysis.11 In 2019, Borges et al demonstrated statistically significant correlations between a high level of sperm DNA fragmentation and poor embryo development, a low implantation rate, and a high miscarriage rate.12 Participants in that study were initially considered to have unexplained infertility. However, sperm abnormalities, in the form of DNA fragmentation, were detected in nearly 10%. These findings suggest that DNA fragmentation is a valuable marker of sperm abnormalities for some men and could be used in combination with a semen analysis to strengthen the diagnostic work-up for male infertility.13
The association between oxidative stress, DNA damage, and poor sperm quality appears to be well-documented. Less clear is whether oxidative stress causes the DNA damage associated with seminal abnormalities. The present study demonstrated notable improvements in oxidative stress, DNA integrity, and sperm quality with antioxidant supplementation in the form of NAC. Other studies on antioxidant therapy for male infertility have reported similar results. However, rigorous studies revealing clear clinical outcomes are limited, and most of the research concludes that further investigation is warranted.14 In the meantime, it appears reasonable to target oxidative stress, whether through antioxidant supplementation or otherwise, in the treatment of male idiopathic infertility. Current options for providers are extensive, with a growing list of antioxidant supplements including selenium, L-carnitine, acetyl-l-carnitine, coenzyme Q10, zinc, folic acid, myo-inositol, vitamin E, vitamin C, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and now NAC.15-20
- Kumar N, Singh AK. Trends of male factor infertility, an important cause of infertility: A review of literature. J Hum Reprod Sci. 2015;8(4):191–196.
- Anawalt B, Page S. Causes of Male Infertility. https://www.uptodate.com/contents/causes-of-male-infertility. Literature review current through June 2019. Accessed July 14, 2019.
- Kothandaraman N, Agarwal A, Abu-Elmagd M, Al-Quatani MH. Pathogenic landscape of idiopathic male infertility: new insight towards its regulatory networks. NPJ Genom Med. 2016;1:16023.
- Wagner H, Cheng JW, Ko EY. Role of reactive oxygen species in male infertility: An updated review of literature. Arab J Urol. 2018;16(1):35–43.
- Human spermatozoa and interactions with oxidative stress. In: Toor JS, Sikka SC. Oxidants, Antioxidants and Impact of the Oxidative Status in Male Reproduction. Elsevier; 2019. https://www.sciencedirect.com/science/article/pii/B9780128125014000067. Accessed July 14, 2019.
- Dutta S, Majzoub A, Agarwal A. Oxidative stress and sperm function: A systematic review on evaluation and management. Arab J Urol. 2019;17(2):87-97.
- Alkan I, Simsek F, Haklar G, Kervancioğlu E, Ozveri H, Yalçin S. Reactive oxygen species production by the spermatozoa of patients with idiopathic infertility: relationship to seminal plasma antioxidants. J Urol. 1997;157:140–143.
- Agarwal A, Prabakaran SA. Mechanism, measurement, and prevention of oxidative stress in male reproductive physiology. Indian J Exp Biol. 2005;43(11):963-974.
- Oladosu OW, Biliaminu SA, Abdulazeez IM, Nwadike VU, Yusuff JO, Okesina AB. Assessment of seminal biomarker of lipid peroxidation among male partners of infertile couples at the University of Ilorin Teaching Hospital in Nigeria. Niger Postgrad Med J. 2018;25(2):94-99.
- Subramanian V, Ravichandran A, Thiagarajan N, Govindarajan M, Dhandayuthapani S, Suresh S. Seminal reactive oxygen species and total antioxidant capacity: Correlations with sperm parameters and impact on male infertility. Clin Exp Reprod Med. 2018 Jun;45(2):88-93.
- Wright C, Milne S, Leeson H. Sperm DNA damage caused by oxidative stress: modifiable clinical, lifestyle and nutritional factors in male infertility. Reprod Biomed Online. 2014 Jun;28(6):684-703.
- Borges E Jr, Zanetti BF, Setti AS, Braga DPAF, Provenza RR, Iaconelli A Jr. Sperm DNA fragmentation is correlated with poor embryo development, lower implantation rate, and higher miscarriage rate in reproductive cycles of non-male factor infertility. Fertil Steril. 2019;112(3):483-490.
- Keshteli SH, Farsi MM, Khafri S. Should we perform semen analysis, DNA fragmentation, and hypo-osmotic swelling tests together? Int J Mol Cell Med. 2016;5(4):246–254.
- Showell MG, Mackenzie-Proctor R, Brown J, Yazdani A, Stankiewicz MT, Hart RJ. Antioxidants for male subfertility. Cochrane Database Syst Rev. 2014;(12):CD007411.
- Buhling K, Schumacher A, Eulenburg CZ, Laakmann E. Influence of oral vitamin and mineral supplementation on male infertility: a meta-analysis and systematic review. Reprod Biomed Online. 2019;39(2):269-279.
- Hosseini B, Nourmohamadi M, Hajipour S, et al. The effect of omega-3 fatty acids, EPA, and/or DHA on male infertility: a systematic review and meta-analysis. J Diet Suppl. 2019;16(2):245-256.
- Busetto GM, Agarwal A, Virmani A, et al. Effect of metabolic and antioxidant supplementation on sperm parameters in oligo-astheno-teratozoospermia, with and without varicocele: A double-blind placebo-controlled study. Andrologia. 2018;50(3).
- Cheng JB, Zhu J, Ni F, Jiang H. L-carnitine combined with coenzyme Q10 for idiopathic oligoasthenozoospermia: A double-blind randomized controlled trial. Zhonghua Nan Ke Xue. 2018;24(1):33-38.
- Condorelli RA, La Vignera S, Mongioì LM, et al. Myo-inositol as a male fertility molecule: speed them up! Eur Rev Med Pharmacol Sci. 2017;21(2 Suppl):30-35.
- Kumalic SI, Pinter B. Review of clinical trials on effects of oral antioxidants on basic semen and other parameters in idiopathic oligoasthenoteratozoospermia. Biomed Res Int. 2014;2014:426951.