Utilization of aminoguanidine prevents cytotoxic effects of semen

Studies of human semen in cell or tissue culture are hampered by the high cytotoxic activity of this body fluid. Responsible for the cell damaging activity of semen are amine oxidases, which convert abundant polyamines such as spermine or spermidine in seminal plasma into toxic intermediates. Amine oxidases are naturally present at low concentrations in seminal plasma and at high concentrations in fetal calf serum, a commonly used cell culture supplement. We here show that in the presence of fetal calf serum, seminal plasma as well as the polyamines spermine and spermidine are highly cytotoxic to immortalized cells, primary blood mononuclear cells, and vaginal tissue. Thus, experiments investigating the effect of polyamines and seminal plasma on cellular functions should be performed with great caution, considering confounding cytotoxic effects. Addition of the amine oxidase inhibitor aminoguanidine to fetal calf serum and/or utilization of serum-free medium greatly reduced this serum-induced cytotoxicity of polyamines and seminal plasma in cell lines, primary cells and tissues, and thus should be implemented in all future studies analyzing the role of polyamines and semen on cellular functions.