Terahertz irradiation-induced motility enhancement and intracellular calcium elevation in human sperm in vitro

To date, there has been limited evidence to reveal the effect of terahertz radiation on sperm. In this study, semen samples were collected from males who had just finished a prepregnancy computer-assisted semen analysis (CASA). The motility, intracellular concentration of free Ca(2+) and DNA integrity of sperm with or without terahertz (0.1 to 3 THz) irradiation at 60 µW/cm(2) were assessed. We found that terahertz irradiation for more than 5 minutes significantly increased the progressive motility percentage of sperm, and the DNA integrity was not changed. We also found that the effect of terahertz irradiation on spermatozoa was weakened by reducing the concentration of extracellular calcium ions or by blocking calcium channels.