title: Local application of platelet-activating factor induces cervical ripening accompanied by infiltration of polymorphonuclear leukocytes in rats.
abstract: OBJECTIVE
  The purpose of this study was to determine the effect of locally applied platelet-activating factor on cervical ripening and leukocyte infiltration.
  
  
  METHODS
  Timed-pregnant rats were treated vaginally twice each day on days 14 and 15 of gestation with platelet-activating factor 5 x 10(-8) mol/L (low-dose), 5 x 10(-7) mol/L (high-dose), or solvent and were killed on day 16. Cervical ripening was assessed by cervical resistance-to-stretch and light-induced autofluorescence of cross-linked collagen. Longitudinal sections of the cervix were hematoxylin and eosin stained, and the number of polymorphonuclear leukocytes in eight high-power fields was determined.
  
  
  RESULTS
  Cervical resistance-to-stretch and light-induced autofluorescence were decreased in rats that were treated with high-dose platelet-activating factor compared with controls (0.4375 +/- 0.0126 N/mm vs 0.5528 +/- 0.0294 N/mm, and 2.739 +/- 0.150 N/mm vs 3.475 +/- 0.236 N/mm; P <.05). High-dose platelet-activating factor led to infiltration with polymorphonuclear leukocytes compared with control (22.1 +/- 5.2 vs 2.1 +/- 1.3 cells/8 high-power fields, P <.05).
  
  
  CONCLUSIONS
  Local platelet-activating factor application induces cervical ripening accompanied by stromal polymorphonuclear leukocyte infiltration. Platelet-activating factor may play a major role in parturition under physiologic and pathologic conditions.
authors.affiliation: Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77550-1062, USA.
authors.forename: Holger
authors.initials: H
authors.lastname: Maul
authors.forename: Leili
authors.initials: L
authors.lastname: Shi
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Marx
authors.forename: Robert E
authors.initials: RE
authors.lastname: Garfield
authors.forename: George R
authors.initials: GR
authors.lastname: Saade
mesh_terms: D000287:Administration, Topical; D000818:Animals; D020070:Cervical Ripening / Q000187:drug effects*; D002584:Cervix Uteri / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005453:Fluorescence; D020556:Neutrophil Infiltration / Q000187:drug effects*; D010972:Platelet Activating Factor / Q000008:administration & dosage* / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values
chemical_list: D010972:Platelet Activating Factor