The hazardous effects of tobacco smoking on male fertility

Abstract

The substantial harmful effects of tobacco smoking on fertility and reproduction have become apparent but are not generally appreciated. Tobacco smoke contains more than 4000 kinds of constituents, including nicotine, tar, carbonic monoxide, polycyclic aromatic hydrocarbons, and heavy metals. Because of the complexity of tobacco smoke components, the toxicological mechanism is notably complicated. Most studies have reported reduced semen quality, reproductive hormone system dysfunction and impaired spermatogenesis, sperm maturation, and spermatozoa function in smokers compared with nonsmokers. Underlying these effects, elevated oxidative stress, DNA damage, and cell apoptosis may play important roles collaboratively in the overall effect of tobacco smoking on male fertility. In this review, we strive to focus on both the phenotype of and the molecular mechanism underlying these harmful effects, although current studies regarding the mechanism remain insufficient.

Figure 1

Schematic representation of the effects of tobacco smoking on male fertility. The figure identifies the main hazardous components of tobacco. Tobacco smoking leads to reduced semen quality including semen volume, sperm density, motility, viability, and normal morphology. Furthermore, reproductive hormone system disorders, dysfunction of spermatogenesis, sperm maturation process, and impaired spermatozoa function have also been observed in smokers. The left part of the figure indicates the underlying mechanism. Increased reactive oxygen species level caused by hazardous components of tobacco will lead to DNA fragmentation and apoptosis which will result in the impairment of sperm function leading to lower male fertility.