Assessing the biological effects of microwave irradiation on human semen in vitro and determining the role of seminal plasma polyamines in this process

Abstract

The aim of the present study was to investigate the influence of millimeter-wave electromagnetic (MW) irradiation on normal and pathological human sperm in vitro, and to evaluate a possible role of polyamines (PA) in this process. The stability of sperm membranes, the number of apoptotic gametes, and the content of seminal plasma PA in the ejaculates of fertile and subfertile men were compared before and after short-term MW electromagnetic exposure in vitro. The ejaculate samples were collected from healthy donors [n=25, age 22-38 years old (y.o.), average age 30.6±1.1 y.o. (mean ± SEM)] and from subfertile men (n=78, age 25-48 y.o., average age 34.1±0.8 y.o.) and exposed to MW radiation. The electromagnetic field had a wavelength of 7.1 mm, a frequency of 42.194 GHz and an exposure time of 20 min. The fragility of sperm membranes was evaluated by their resistance to sodium chloride solution (Milovanov test) and to acetic acid (Joel test). Acrosin activity was assayed spectrophotometrically. Apoptosis was determined by the externalization of phosphatidylserine on the outer side of the sperm membrane and propidium iodide staining. The PA levels were determined by agar gel electrophoretic fractionation. An increase in the resistance of sperm membranes, a decrease in acrosin activity, a decrease in the number of apoptotic gametes and a decrease in the seminal plasma PA concentrations were found after exposure of the native human sperm to low-intensity MW irradiation. Two types of reactions were revealed for the subfertile samples. The results revealed positive bio-effects of specific microwaves on the human semen and the participation of PA in the realization of these effects.

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“…Based on our experience, free SPD compound shows no cytotoxicity on NIH/3T3 cells [ 18 ] as well as L929 and RAW 264.7 cells (data not shown) up to 5 µM, but higher concentration of SPD greater than 10 µM may cause some cell death. It is also known that the concentration of SPD in normal human semen varies in the range of 0.25 to 1.17 mM, [ 44 ] which is ≈2 magnitudes larger than the tolerable concentration in cell culture. This seeming discrepancy is due to the different scenarios of in vitro and in vivo experiments.…”

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“…Alternatively, an increase in the resistance of sperm membranes, as well as a decrease in acrosin activity, number of apoptotic gametes, and seminal plasma PA concentrations, were found following exposure of native human sperm to low-intensity microwave irradiation. Two types of reactions were observed in the sub-fertile samples, and the results revealed the positive bio-effects of specific microwaves on human semen, in addition to the participation of PA in the realization of these effects [ 58 ].…”