Apoptosis in Spermatozoa and Its Role in Deteriorating Semen Quality

Abstract

The importance of sperm DNA integrity is hard to overestimate since the quality of the genetic material in a sperm population is the key point for successful fertilization, the embryonic and subsequent development of offspring, and, therefore, the male reproductive potential. Apoptosis is essential for male gametes in the period from the time of appearance of the gonadal anlagen in the embryo to the moment of fertilization. This mechanism of programmed cell death is necessary to maintain the appropriate ratio between the germ cells and the Sertoli cells during prenatal development. The damaged cells are removed from the testicles in the adult specimens by the apoptosis pathway. A range of unfavorable effects can intensify this process. In addition, mature spermatozoa undergo apoptosis and subsequent phagocytosis in the female reproductive tract in order to prevent the inflammatory response triggered by the dead gamete destruction. The impaired process of apoptosis may cause developmental abnormalities in male gametes, infertility, and fertilization of oocyte by sperm with DNA damage followed by subsequent offspring death. Therefore, recent studies show that apoptosis is one of the main causes of sperm DNA fragmentation, which tends to become a significant problem under conditions for the widespread use of assisted reproductive technologies.