Discussion
In this study, we found that antioxidant treatments had a positive effect on sperm parameters and that the two different molecule combinations had similar effects. Male infertility may be the result of some identifiable conditions (varicocele, cryptorchidism, hypogonadism, and genetic abnormalities), but no cause can be identified in 30-40% of infertile men. Such idiopathic infertility is characterized by decreased spermatozoa, decreased sperm motility, and abnormal sperm morphology in men that have no history of fertility-impairing disease and normal findings in physical examination and laboratory tests (Cooper et al., 2010).
It is assumed that various factors may be effective in idiopathic OAT, including endocrine disorders, genetic abnormalities, and ROS (Jungwirth et al., 2013). High ROS levels and oxidative stress have been associated with sperm DNA damage, decreased sperm motility, and impaired fertilization and embryo development (Agarwal et al., 2014). Since ROS damages lipids, amino acids, carbohydrates, proteins, and DNA of spermatozoa, this also affects sperm function (Agarwal et al., 2003). Therefore, targeting OS is considered to be a strategy to increase fertility and spermatozoa count and quality. Studies have shown that in addition to vitamins (mainly A, B, C and E) and non-enzymatic antioxidants including glutathione, metabolic coenzymes such as pantothenic acid, CoQ10 and carnitines (l-carnitine and acetyl-l-carnitine) and micronutrients (zinc, selenium, and copper) have beneficial effects on fertility, especially sperm quality, and they are therefore recommended as a potentially effective treatment for male infertility (Walczak-Jedrzejowska, Wolski, & Slowikowska-Hilczer, 2013).
Several studies have reported that antioxidant therapy can reverse sperm DNA damage and improve other sperm parameters (Majzoub et al., 2017) In a meta-analysis, Omar et al. (2019) compared CoQ10 and L-carnitine with a placebo and concluded that antioxidants could protect against free radical damage in infertile men with higher ROS levels. Antioxidants were also found to improve spermatogenic function and sperm DNA integrity (Elumalai et al., 2009). Various clinical trials and systemic studies including the use of various combinations of antioxidants (L-carnitine, selenium, N-acetylcysteine, CoQ10, ubiquinol, vitamin E, vitamin C, and lycopene) in infertile men reported the beneficial effects of antioxidants on sperm concentration and motility and DNA integrity (Agarwal et al.,2019 ). Abad et al. (2013) also conducted a study to determine the effect of oral antioxidant therapy on the dynamics of sperm DNA fragmentation in a cohort of 20 infertile patients diagnosed with asthenoteratozoospermia. All subjects were given a combination of 1,500 mg L-carnitine, 60 mg vitamin C, 20 mg CoQ10, 10 mg vitamin E, 10 mg zinc, 200 microgram folic acid, 50 microgram selenium and 1 microgram vitamin B12 for a period of three months. The results showed that the rate of sperm with DNA damage was significantly reduced, and there was a significant increase in the concentration, motility, viability and morphology parameters of the semen analysis data. Furthermore, a significant improvement in DNA integrity was observed at all incubation points. The findings of that study were considered to indicate that antioxidant therapy helped preserve sperm quality not only in terms of important seminal parameters and basal DNA damage but also DNA integrity. In another study, Gopinath et al. (2013) noted that the administration of antioxidants in men with OAT resulted in a significant improvement in their sperm count and total motility at 90 days compared with the placebo.
Tremellen et al. (2007) conducted a prospective, randomized, double-blind, placebo-controlled study in 60 couples with severe male factor infertility. The participants were randomly assigned to take either one capsule of a combination containing 6 mg lycopene, 400 IU vitamin E, 100 mg vitamin C, 25 mg zinc, 26 microgram selenium, 5 mg folate, and 1,000 mg of garlic or a placebo three months before their partners’ in vitro fertilization or intracytoplasmic sperm injection (IVF or ICSI) cycle. The antioxidant group showed a statistically significant improvement in live pregnancy rates (38.5%) compared to the control group (16%). A meta-analysis by Lafuente et al. (2013) showed that treatment with CoQ10 resulted in a significant improvement in sperm motility and density, but no significant improvement was observed in live birth or pregnancy rates. In another study, combination therapy with carnitine, CoQ10, vitamin E and vitamin C for three to six months improved sperm concentration (Gvozdjáková et al., 2015).
In a systematic review published by Ross et al. in 2010, 17 randomized studies were selected to evaluate the effects of oral antioxidants on sperm quality and pregnancy rate in infertile men. The results showed that the treatment of infertile men with oral antioxidants could reduce seminal OS and improve sperm motility, but had a less predictable effect on sperm concentration and morphology. In addition, oral antioxidant therapy was associated with a significant improvement in spontaneous and assisted pregnancy rates in six of 10 randomized studies included in the analysis (Ross et al., 2010). In our study, the positive effects of two different combinations on sperm parameters were determined. Since there was no placebo group, it is not possible to comment on spontaneous pregnancy rates; however, there was a significant increase on the morphology values ​​of both molecules.
Showell et al. (2011) evaluated whether supplementation with oral antioxidants would improve the results of assisted reproductive techniques when used in the male partners of couples undergoing assisted reproductive techniques (ART), and how antioxidants might affect the pregnancy rate, sperm parameters, and sperm DNA fragmentation. Data from 34 studies including a total of 2,876 couples were included in the analysis. Antioxidant treatment was associated with a statistically significant increase in the rates of live birth [odds ratio: 4.85, 95% confidence interval (CI): 1.92-12.24; p = 0.0008]and pregnancy (OR: 4.18, 95% CI: 2.65-6.59; p<0.00001) compared to the control groups (Showell et al., 2011). In a recent review, Clark et al. (2013) examined 37 randomized controlled trials on complementary and alternative medicine, including antioxidants and nutritional supplements for the treatment of male infertility. Despite the presence of some preliminary evidence of the efficacy of antioxidant interventions among infertile patients, the authors emphasized the need for further research before the adoption of these modalities in routine clinical use (Clark et al. 2013). Similar conclusions were reached by Imamovic Kumalic et al. (2017), who reviewed 32 studies conducted from 2000 to 2013 and found that most confirmed the beneficial effect of antioxidants on at least one semen parameters, with the most prominent effect being on sperm motility, as well as the possible role of dietary supplements in the treatment of idiopathic OAT.
In a study by Kızılay et al (2019)., infertile patients who underwent varicocelectomy were given antioxidants together with surgical treatment, and it was determined that the antioxidant + surgical treatment group achieved statistically significant results in relation to semen parameters and spontaneous pregnancy. In another recent study, patients with high-grade varicoceles were randomized to surgical treatment and L-carnitine supplementation groups, and favorable results were obtained in all sperm parameters with motility increasing from 21.7 to 35.4% and 33.9 to 47.5%, respectively; normal sperm morphology from 46.3 to 60% and 56.6 to 69.7%, respectively, and seminal volume from 3.5 to 4.2 ml and 2.9 to 4.3 ml, respectively. The authors concluded that additional therapy was as effective as varicocelectomy in improving semen parameters, and could therefore be used as an alternative to surgery (Sofimajidpour, Ghaderi, & Ganji, 2016). In a study by Busetto et al. (2018) the effect of treatment on varicocele-induced infertility was evaluated by applying an adjuvant antioxidant or placebo to 114 patients with and without varicoceles. A significant increase was found in semen parameters and pregnancy rates of the group that had received antioxidant supplementation for six months.
Many studies in the literature report positive results regarding different agents and application methods and different doses of antioxidant treatments. The groups given antioxidant treatments together with ART, after varicocelectomy, or in patients with varicocele were observed to have significant improvements compared to the untreated groups. Due to the methodological and clinical heterogeneity of these studies, it is difficult to make a comparison between the agents administered or to make a definitive conclusion on the optimal dose and duration for a given oral treatment. In our study, both antioxidant combinations, which differ in terms of content, providing significant results compared to the baseline values, shows that the use of this treatment in infertile patients is useful. However, the two molecules with different content screating similar effects raises further questions concerning the molecules contained in each combination and their dose.
The limitations of this study include the absence of a placebo group and an evaluation of sperm DNA damage not being undertaken.