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

Abstract

Sperm preparation procedures are a potential generator of oxidative stress-induced DNA damage, which leads to a dramaticdrop 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. Labelingwith anti-CD46 and antiactive caspase-3 allowed the monitoring of acrosome reaction and apoptosis by flow cytometry. Sperm DNAfragmentation and compaction were analyzed through propidium iodide staining. The normozoospermic and oligozoospermicsamples that were preincubated with melatonin underwent a significant increase in the ratio of adequate spermatozoa and a reductionof caspase-3 activation. Additionally, preincubation with melatonin enhanced the migration of sperm cells with compacted DNA inoligozoospermic samples (P < 0.05) and prevented DNA fragmentation in normozoospermic samples (P < 0.05). In light of the currentresults, the cytoprotective capacity and innocuousness of melatonin make it a great candidate to be applied in assisted reproductiontechniques in order to prevent iatrogenic oxidative damage.