Previous studies have reported ROS increase in the sperm of infertile men with varicocele (
24-
26). So, therapies with antioxidant properties are recommended in these patients to prevent ROS damage to metabolism, sperm motility, and morphology and to increase the fertility capacity. Many antioxidants have been studied and their role in decreasing infertility through sperm motility improvement is demonstrated (
27).
In this randomized clinical trial, we evaluated the effect of saffron, a herb with anti-oxidant properties, on sperm parameters in patients with clinical varicocele undergoing varicocelectomy and found that six month treatment with saffron significantly improved sperm motility but had no effect on other parameters.
There are only three studies on animal models and two studies on male infertile subjects evaluating the effect of saffron on sperm parameters (
16-
20). Although animal studies were indicative of the potential role of saffron in improving all semen parameters (
16-
18), studies on humans could not confirm these results. Heidary et al. (
19) observed that saffron is effective on sperm morphology and motility in nonsmoker infertile men with oligospermia, but it does not increase sperm count. However, Safarinejad et al. (
20) in their research on saffron showed no statistically significant improvements in any of the studied semen parameters in infertile males with idiopathic oligoasthenoteratozoospermia compared with placebo group. In this study, we only found significant improvement in sperm motility. The dissimilarity between animal and human studies may be caused by inherent differences between rats and humans and also it could be due to administrating different doses and the treatment period.
Previous studies have recommended that saffron improves sperm parameters by its antioxidant properties to prevent oxidative stress (
15,
28).
Oxidative stress is induced by ROS or free radicals. ROS are needed for capacitation, the acrosome reaction, and ultimately fertilization; however, excessive levels of ROS may damage a variety of biomolecules such as lipids, amino acids, carbohydrates, protein, and DNA and negatively impact sperm quality (
8,
9). It is shown that increased levels of ROS are correlated with decreased sperm motility (
29), increased sperm DNA damage (
30), sperm cellular membrane lipid peroxidation (
31), and decreased efficacy of oocyte–sperm fusion (
32). These free radicals induce sperm cell injury through several pathways and can significantly impact both sperm quality and function (
32,
33).
Recent systemic reviews of the oral antioxidants on male infertility reported improvement in either sperm quality after antioxidant therapy due to their role in protecting semen from ROS (
27,
34). However, Safarinejad et al. (
20) observed that saffron does not significantly improve total seminal plasma antioxidant capacity. It is possible that saffron does not have proper effects on male infertility, but further studies are necessary in this regard.
Our study has some limitations. The low sample size is an important limitation of our study which could have affected the results. We did not evaluate the ROS levels, neither total seminal plasma antioxidant capacity nor their change during the treatment with saffron and could not conclude about the saffron effects in these regards. Most studies on human have evaluated the saffron effects compared to placebo and did not compare their efficacy with other antioxidants. Further studies are necessary to clarify the exact role of saffron on sperm parameters.
4.1. Conclusion
Our results showed that except improving sperm motility, saffron has no effect on other semen parameters in infertile male with clinical varicocele after varicocelectomy. However, further studies are necessary to evaluate the effective suitable dose, prescription fashion, and prescription intervals.