Melatonin diminishes oxidative damage in sperm cells, improving assisted reproductive techniques.

Fabián Monllor,Águeda Ortiz,Juan Francisco García,Javier Espino,Ignacio Bejarano,Ana Beatriz Rodríguez,José Antonio Pariente,Graciela Lozano,Ana María Marchena

doi:10.3906/biy-1704-45

Abstract

Sperm preparation procedures are a potential generator of oxidative stress-induced DNA damage, which leads to a dramatic drop in fertility. An increasing number of studies suggest that melatonin reduces the oxidative stress induced by manipulation. However, very little is known about the preservative role of melatonin in sperm preparation medium during assisted reproduction procedures. For this aim to be achieved, semen was divided into two fractions and preincubated with and without 1 mM melatonin. Afterwards, both fractions were divided into two subfractions to perform swim-up in the presence and absence of 1 mM melatonin. Labeling with anti-CD46 and antiactive caspase-3 allowed the monitoring of acrosome reaction and apoptosis by flow cytometry. Sperm DNA fragmentation and compaction were analyzed through propidium iodide staining. The normozoospermic and oligozoospermic samples that were preincubated with melatonin underwent a significant increase in the ratio of adequate spermatozoa and a reduction of caspase-3 activation. Additionally, preincubation with melatonin enhanced the migration of sperm cells with compacted DNA in oligozoospermic samples (P < 0.05) and prevented DNA fragmentation in normozoospermic samples (P < 0.05). In light of the current results, the cytoprotective capacity and innocuousness of melatonin make it a great candidate to be applied in assisted reproduction techniques in order to prevent triaogenic oxidative damage.

Highlights

Surveys indicate that 9%–15% of couples endure a prevalence of infertility after 12 months of unprotected intercourse, and 56% of them seek medical care to conceive (Boivin et al, 2007; Agarwal et al, 2014b)
In both normozoospermic and oligozoospermic samples, flow cytometry indicated a decrease in the ratio of active caspase-3 labeling after preincubation with melatonin (Prm) (Figures 3A and 3B)
In light of these results, melatonin could be used to protect sperm cells in those cases in which the swim-up assortment is not carried out. Both in normozoospermic and oligozoospermic, antiCD46 labeling revealed an increase in the ratio of adequate sperm cells when fresh samples were preincubated with 1 mM melatonin (Prm) (Figure 4)

Summary

Introduction

Surveys indicate that 9%–15% of couples endure a prevalence of infertility after 12 months of unprotected intercourse, and 56% of them seek medical care to conceive (Boivin et al, 2007; Agarwal et al, 2014b). The spermatozoon is a very sensitive cell to ROS-induced oxidative damage. This is partly due to the fact that the sperm plasma membrane contains a high content of polyunsaturated fatty acid, which confers to sperm cells the needed fluidity for membrane fusion during fertilization (Makker et al, 2009). The presence of ROS in the seminal fluid can originate from several sources, both endogenous and exogenous. In this sense, cellular components (mature and immature sperm cells, leukocytes, and urogenital epithelial cells) of human semen are considered the major source of ROS, especially leukocytes and immature sperm cells

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