Bacteria trigger oxygen radical release and sperm lipid peroxidation in in vitro model of semen inflammation.

OBJECTIVE

To assess the in vitro effect of five bacterial strains isolated from semen samples (Escherichia coli, Staphylococcus haemolyticus, Streptococcus oralis, Bacteroides ureolyticus, and Ureaplasma urealyticum) on reactive oxygen intermediate (ROI) release and lipid sperm membrane peroxidation in the coincubated suspensions of white blood cells (WBC) with spermatozoa.

DESIGN

An in vitro model of semen infection.

SETTING

Basic research laboratory.

PATIENT(S): Healthy normozoospermic volunteers and healthy blood donors.

INTERVENTION(S): None.

MAIN OUTCOME MEASURE(S): Chemiluminescent assay was used to evaluate ROI generation by WBC. Malondialdehyde (MDA) concentration was determined in sperm lysates using high-performance liquid chromatography.

RESULT(S): Of the bacterial strains tested, B. ureolyticus, S. haemolyticus, and E. coli caused the greatest damage to sperm membrane lipids. An increase in MDA levels in sperm lysates was a natural consequence of bacteria-induced ROI generation. The WBC usually enhanced harmful activity of the infectious agent toward the cell membranes.

CONCLUSION(S): The harmful effect of bacteria on spermatozoa depends on the type and species of microorganisms invading, colonizing, or infecting the male genital tract and is associated with the accompanying oxidative stress. The presence of leukocytes in semen appears to be the additional factor enhancing the sperm lipid membrane peroxidation, which may affect the fertility status.