title: Can apoptosis and necrosis coexist in ejaculated human spermatozoa during in vitro semen bacterial infection?
abstract: OBJECTIVE
  To evaluate whether ejaculated human spermatozoa undergo complete apoptosis or necrosis during experimental semen bacterial infection in vitro.
  
  
  METHODS
  Apoptotic markers, including mitochondrial transmembrane potential (ΔΨm), phosphatidylserine (PS) externalization, and DNA fragmentation, have been detected simultaneously in ejaculated human sperm after their incubation with a known pathogenic (Escherichia coli), as well as with conditionally pathogenic bacterial strains (Staphylococcus haemolyticus, Bacteroides ureolyticus) and/or leukocytes. The ΔΨm and translocation of PS was evaluated using the JC-1 and Annexin V binding tests, respectively. A modified TUNEL assay with additional staining for sperm viability was used to detect the DNA fragmentation level.
  
  
  RESULTS
  The exposure of ejaculated spermatozoa to bacterial strains was associated with a simultaneous decrease in the percentage of sperm with normal ΔΨm and an increase in the proportion of Annexin V-positive sperm. Additionally, in the presence of S. haemolyticus, B. ureolyticus and/or leukocytes, a significant increase in the percentage of live TUNEL-positive (apoptotic) as well as dead TUNEL-positive (necrotic) sperm cells was also observed.
  
  
  CONCLUSIONS
  The cellular death observed in spermatozoa in the presence of inflammatory mediators may be due to both apoptosis and necrosis. Here, we demonstrate for the first time that direct contact of conditionally pathogenic bacteria with ejaculated human sperm may play an even greater role in the promotion of apoptosis than in case of some pathogenic bacterial strains. These findings suggest that significant bacteriospermia and leukocytospermia may be direct causes of subfertility or additional negative factors worsening the prognosis of fertility in natural and assisted procreation.
authors: Department of Reproductive Biology and Stem Cells, Institute of Human Genetics, Polish Academy of Sciences, Strzeszynska 32, 60-685, Poznan, Poland.
authors: Monika
authors: M
authors: Fraczek
authors: Magdalena
authors: M
authors: Hryhorowicz
authors: Dariusz
authors: D
authors: Gaczarzewicz
authors: Anna
authors: A
authors: Szumala-Kakol
authors: Tomasz J
authors: TJ
authors: Kolanowski
authors: Lothar
authors: L
authors: Beutin
authors: Maciej
authors: M
authors: Kurpisz
mesh_terms: D000328:Adult; D017209:Apoptosis; D001419:Bacteria / Q000145:classification / Q000472:pathogenicity; D001424:Bacterial Infections / Q000382:microbiology / Q000473:pathology*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D053078:Membrane Potential, Mitochondrial; D009336:Necrosis; D012661:Semen / Q000382:microbiology*; D013081:Sperm Motility; D013094:Spermatozoa / Q000382:microbiology* / Q000473:pathology*; D055815:Young Adult