Role of genitourinary inflammation in infertility: Synergistic effect of lipopolysaccharide and interferon-γ on human spermatozoa

Pro-inflammatory cytokines are elevated in the semen of patients with genitourinary inflammation (GUI). Whether this increase in cytokines in GUI patients plays any critical role in male factor infertility is not clear. The present study investigated the in vitro effects of two important pro-inflammatory cytokines, lipopolysaccharide (LPS) and interferon-γ (IFN-γ), on sperm motility, viability, membrane integrity and motion parameters. Washed spermatozoa from healthy donors were incubated with LPS (0.1 mg/mL) or IFN-γ (0.1 mg/mL) alone or in combination. Sperm motility, viability, membrane integrity and computer-assisted motion were evaluated at various time intervals (0, 30, 60 and 180 min) after treatment. Sperm membrane integrity was analysed using the hypoosmotic swelling test (HOST). LPS and IFN-γ individually did not alter sperm viability or motility, but their combination showed a significant time-dependent decrease (p < 0.05) in sperm motility, viability and membrane integrity. Sperm motion parameters (straight-line velocity, curvilinear velocity, mean linearity, or amplitude of lateral head displacement) were not affected by LPS or IFN-γ at the concentrations used in this study. These data suggest that the combination of LPS and IFN-γ is detrimental to human spermatozoa and may contribute to male factor infertility in patients with chronic GUI.