title: Effect of tumor necrosis factor-α on the intracellular Ca(2+) homeostasis in human sperm.
abstract: OBJECTIVE
  Inflammation and genital infections promote the increase in leukocytes, pro-inflammatory cytokines, and oxygen reactive species, impairing sperm functions such as motility, capacitation, and acrosome reaction. All these functions are primarily regulated by cytoplasmic concentration of Ca(2+) ([Ca(2+) ]cyto ). This study evaluated the effect of tumor necrosis factor (TNF)-α on the [Ca(2+) ]cyto and its regulation in human sperm.
  
  
  METHODS
  Sperm loaded with fura-2 were incubated with or without TNF-α (0-500 pg/mL) from 0 to 120 min. After incubation, the basal [Ca(2+) ]cyto and membrane permeability to Ca(2+) were evaluated by spectrofluorometry, before and after Ca(2+) addition to the extracellular medium.
  
  
  RESULTS
  Without TNF-α, the addition of Ca(2+) promotes an transitory increase in [Ca(2+) ]cyto in the spermatozoa, that returns in a few minutes to a basal level, indicating calcium regulation activation. TNF-α decreases the Ca(2+) permeation and increases the basal level of [Ca(2+) ]cyto after a Ca(2+) pulse (P < 0.04); affecting calcium regulation in a way that is time and concentration dependent. TNF-α effect was partially prevented by the addition of an antioxidant (butylated hydroxytoluene) (P < 0.03).
  
  
  CONCLUSIONS
  Tumor necrosis factor-α decreases membrane permeability to Ca(2+) and affects Ca(2+) regulation in sperm cells in vitro, probably via lipid peroxidation, which may explain the decrease in sperm fertilizing capacity during inflammatory and infectious processes.
authors.affiliation: Departamento de Biología de Organismos, Universidad Simón Bolívar, Caracas, Venezuela. gcarrasquel@usb.ve
authors.forename: Gabriela
authors.initials: G
authors.lastname: Carrasquel
authors.forename: Maria I
authors.initials: MI
authors.lastname: Camejo
authors.forename: Fabian
authors.initials: F
authors.lastname: Michelangeli
authors.forename: Marie C
authors.initials: MC
authors.lastname: Ruiz
mesh_terms: D020101:Acrosome Reaction; D000328:Adult; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism; D002478:Cells, Cultured; D005306:Fertilization; D016257:Fura-2 / Q000494:pharmacology; D006706:Homeostasis; D006801:Humans; D017136:Ion Transport / Q000187:drug effects*; D008297:Male; D013075:Sperm Capacitation / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D014409:Tumor Necrosis Factor-alpha; D002118:Calcium; D016257:Fura-2
keywords: butylated hydroxytoluene antioxidant; human sperm; intracellular Ca2+; lipid peroxidation; tumor necrosis factor-α