Effects of Aging on Mammalian Spermatogenesis From a Cellular Perspective

Aging refers to the irreversible changes in the structure and function of organisms over time. Under the influence of social and economic factors, the apparent effect of aging on female fertility has been widely recognized; however, its effect on male fertility has not received sufficient attention. Spermatogenic stem cells can differentiate and produce gametes continuously for a long time in a man's life, but more significant cumulative effects often occur over time. These age-related effects mainly manifest as increased chromosomal abnormalities and DNA damage, lower levels of sex hormones, impaired testicular function, and reduced spermatozoa count and quality. In the past, more attention has been paid to some of the macroscopic changes associated with aging. In this review, we will focus on the cellular level, discussing the effects of aging on male germ cells and the changes in the spermatogenic microenvironment, which consists mainly of Sertoli and Leydig cells.