In vitro effects of zinc, D-aspartic acid, and coenzyme-Q10 on sperm function.

Reactive oxygen species favor reproductive processes at low concentrations, but damage spermatozoa and decrease their fertilizing capacity at high concentrations. During infection and/or inflammation of the accessory sex glands reactive oxygen species overproduction may occur which, in turn, may negatively impact on sperm motility, sperm DNA fragmentation, and lipid peroxidation. A number of nutraceutical formulations containing antioxidant molecules have been developed to counteract the deleterious effects of the oxidative stress. A recent formulation containing zinc, D-aspartic acid, and coenzyme-Q10 is present in the pharmaceutical market. Based on these premises, the aim of the present study was to evaluate the effects of this combination on spermatozoa in vitro. The study was conducted on 24 men (32.2 ± 5.5 years): 12 normozoospermic men and 12 asthenozoospermic patients. Spermatozoa from each sample were divided into two control aliquots (aliquot A and B) and an aliquot incubated with zinc, D-aspartic acid, and coenzyme-Q10 (aliquot C). After 3 h of incubation, the following parameters were evaluated: progressive motility, number of spermatozoa with progressive motility recovered after swim-up, lipid peroxidation, and DNA fragmentation. Incubation with zinc, D-aspartic acid, and coenzyme-Q10 maintained sperm motility in normozoospermic men (37.7 ± 1.2 % vs. 35.8 ± 2.3 % at time zero) and improved it significantly in asthenozoospermic patients (26.5 ± 1.9 % vs. 18.8 ± 2.0 % at time zero) (p < 0.01). This resulted in a significantly higher (p < 0.01) number of spermatozoa with progressive motility recovered after swim-up in both normozospermic men (4.1 ± 0.9 vs. 3.3 ± 1.0 millions) and asthenozooseprmic patients (3.2 ± 0.8 vs. 1.6 ± 0.5 millions). Finally, a statistically significant lower sperm lipid peroxidation was found after incubation with zinc, D-aspartic acid, and coenzyme-Q10 (p < 0.05) in both normozospermic men (1.0 ± 0.4 % vs. 2.4 ± 0.9 %) and asthenozooseprmic patients (0.2 ± 0.1 % vs. 0.6 ± 0.2 %). No statistically significant effect was observed on sperm DNA fragmentation. This nutraceutical formulation may be indicated in vitro during the separation of the spermatozoa in the assisted reproduction techniques, during which the spermatozoa undergo an increased oxidative stress.