title: Stretching of fetal membranes increases the concentration of interleukin-8 and collagenase activity.
abstract: OBJECTIVE
  The aim of this study was to determine whether stretching of fetal membranes can increase interleukin-8 concentration and collagenase activity.
  
  
  METHODS
  Strips of whole fetal membranes, amnion, or muscles of the lower uterine segment were stretched for 2 or 4 hours. Interleukin-8 and collagenase activity were measured in homogenized control and stretched samples. Immunohistochemical staining for interleukin-8 was carried out.
  
  
  RESULTS
  The interleukin-8 concentration increased significantly after the whole fetal membranes were stretched for 2 and 4 hours (p <0.0007 and 0.001, respectively). Also, stretching of amnion and muscles of the lower uterine segment for 2 and 4 hours increased the concentration of interleukin-8 significantly (p <0.0007 after 2 and 4 hours, respectively). Collagenase activity was significantly increased after stretching of amnion, amniochorion, and muscles of the lower uterine segment for 4 hours (p <0.0007, 0.006, and 0.0007, respectively). After stretching, samples were darkly stained for interleukin-8 compared with control nonstretched samples.
  
  
  CONCLUSIONS
  Stretching of amnion, amniochorion, and muscles of the lower uterine segment increased interleukin-8 production and collagenase activity.
authors.affiliation: Department of Obstretrics and Gynecology, Hamamatsu University School of Medicine, Japan.
authors.forename: E E
authors.initials: EE
authors.lastname: Maradny
authors.forename: N
authors.initials: N
authors.lastname: Kanayama
authors.forename: A
authors.initials: A
authors.lastname: Halim
authors.forename: K
authors.initials: K
authors.lastname: Maehara
authors.forename: T
authors.initials: T
authors.lastname: Terao
mesh_terms: D000650:Amnion / Q000378:metabolism; D002823:Chorion / Q000378:metabolism; D017364:Collagenases / Q000378:metabolism*; D005321:Extraembryonic Membranes / Q000201:enzymology / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016209:Interleukin-8 / Q000378:metabolism*; D009215:Myometrium / Q000378:metabolism; D011247:Pregnancy
chemical_list: D016209:Interleukin-8; D017364:Collagenases