title: Human sperm chromatin undergoes physiological remodeling during in vitro capacitation and acrosome reaction.
abstract: Capacitation (CAP) and acrosome reaction (AR) are sequential processes of  sperm activation. Beside the known ionic, membrane, and transduction events  and final release of proteolytic enzymes that help sperm movement toward the  egg, chromatin changes, such as a physiological remodeling, are also possible.  Our aims were to ascertain that CAP and AR do not induce DNA damage and to  evaluate changes occurring in the human sperm head during these physiological  processes using cytochemical stains. Percollpurified spermatozoa from normal  donors were incubated in Biggers, Whitten, and Whittingham medium ±  fetal cord serum ultrafiltrate (CAP inducer) and then with  lysophosphatidylcholine (AR inducer). CAP and AR were associated with  increases in aniline blue (AB, for histones; ∼70%) and toluidine blue (TB,  for chromatin compaction; ∼40%) staining but had no influence on that of  chromomycin A3 (for protamines). The increase (∼40%) in  iodoacetamide-fluorescein (IAF, for sulfhydryl groups) staining observed  during CAP was absent after AR. CAP and AR did not damage DNA (percentage of  DNA fragmentation index remained low) nor affect histone content. CAP, and  even more AR, primed sperm heads to decondense (∼80% and ∼140%  increases, respectively) when challenged with sodium dodecyl sulfate +  dithiothreitol. Interestingly, induced decondensation correlated with all  other tests (CAP, AB, TB, and IAF). Therefore, the data strongly support a  physiological remodeling of nondamaged human sperm chromatin during CAP and  AR, and modifications are probably interlinked and help prepare chromatin for  postfertilization events.
authors.affiliation: Urology Research Laboratory, McGill University Health Center at the Royal Victoria Hospital and Faculty of Medicine, McGill University, H 6.47, Hôpital Royal Victoria, 687 ave des Pins ouest, Montréal, QC H3A 1A1, Canada. edelamirande@yahoo.com
authors.forename: E
authors.initials: E
authors.lastname: de Lamirande
authors.forename: M C
authors.initials: MC
authors.lastname: San Gabriel
authors.forename: A
authors.initials: A
authors.lastname: Zini
mesh_terms: D020101:Acrosome Reaction / Q000187:drug effects; D042002:Chromatin Assembly and Disassembly / Q000187:drug effects; D004249:DNA Damage; D004229:Dithiothreitol / Q000494:pharmacology; D006657:Histones / Q000378:metabolism; D006801:Humans; D008244:Lysophosphatidylcholines / Q000494:pharmacology; D008297:Male; D011479:Protamines / Q000378:metabolism; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013075:Sperm Capacitation / Q000187:drug effects; D013077:Sperm Head / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D013194:Staining and Labeling / Q000379:methods
chemical_list: D006657:Histones; D008244:Lysophosphatidylcholines; D011479:Protamines; D012967:Sodium Dodecyl Sulfate; D004229:Dithiothreitol