Interferon γ, IL-17, and IL-1β impair sperm motility and viability and induce sperm apoptosis

Urogenital inflammation is a known cause of male infertility. Increased levels of inflammatory cytokines, leukocyte counts and oxidative stress are highly detrimental for sperm quality thus compromising male fertility. Although cytokines affect sperm by recruiting and activating leukocytes consequently inducing tissue inflammation and oxidative stress, scarce to absent data have been reported about the putative direct effects of inflammatory cytokines on spermatozoa. Herein, we analyzed whether IFNγ, IL-17A, IL-1β, and IL-8 can alter human sperm motility and viability per se. Fractions of viable and motile spermatozoa from normospermic healthy donors were in vitro incubated with recombinant human IFNγ, IL-17A, IL-1β or IL-8 and sperm ROS production, motility, viability and apoptosis were analyzed. Sperm exposed to different concentrations of IFNγ, IL-17A and IL-1β, or a combination of them, for either 1 or 3 h showed significantly increased levels of mitochondrial ROS production and reduced motility and viability with respect to sperm incubated with vehicle. Moreover, the exposure to IFNγ, IL-17A and IL-1β resulted in significantly higher levels of early and/or late apoptotic and/or necrotic spermatozoa. Interestingly, no significant differences in sperm motility, viability and apoptosis were observed in sperm incubated with the concentrations of IL-8 analyzed, for either 1 or 3 h, with respect to sperm incubated with vehicle. In conclusion, our results indicate that IFNγ, IL-17A and IL-1β per se impair sperm motility and decreases viability by triggering increased mitochondrial ROS production and inducing sperm apoptosis. Our results suggest that screening inflammatory cytokines in semen would be an additional helpful tool for the diagnostic workup of male infertility.