Embryotoxicity of magainin-2-amide and its enhancement by cyclodextrin, albumin, hydrogen peroxide and acidification

BACKGROUND: The channel-forming antimicrobial peptide, magainin-2-amide, in teracts preferentially with negatively charged, non cholesterol-containing membranes, including those of sperm, oocytes and cells of preimplantation e mbryos, Cyclodextrin and albumin remove membrane cholesterol and together w ith hydrogen peroxide (H2O2) are potential enhancers of embryotoxicity, MET HODS: Two-cell murine embryos were cultured in vitro with magainin-2-amide at a high effective concentration (250 mug/ml) and at subthreshold concentr ations (166 and 200 mug/ml). Embryos treated with sub-threshold concentrati ons of magainin were additionally treated with cyclodextrin, bovine serum a lbumin or H2O2 Or were cultured under acidified conditions. Cell viability was verified with propidium iodide and fluorescein diacetate. RESULTS: The embryotoxic effect of magainin and H2O2 was dose- and time-dependent. Cyclo dextrin, H2O2, acidification of the medium, and to a lesser extent albumin, enhanced the embryotoxicity of magainin at sub-threshold concentrations. C ONCLUSION: Magainin on its own is highly embryotoxic, Its embryotoxicity is enhanced by cyclodextrin, albumin, H2O2 and acidification. Thus, magainin which has antibacterial, antifungal and antiprotozoal activity may also hav e a potential role as a contraceptive agent, The harmful effects of various concentrations of the exogenous H2O2 on 2-cell stage mouse embryos are rep orted here, to the best of our knowledge, for the first time.