title: [Expression of claudin-4 in eutopic and ectopic endometrium of women with endometriosis].
abstract: OBJECTIVE
  To investigate the expression of claudin-4 in the eutopic and ectopic endometrium of women with endometriosis and evaluate the role of claudin-4 in the pathogenesis of endometriosis.
  
  
  METHODS
  Thirty-five women with endometriosis and 35 controls were studied. Expression of claudin-4 was investigated using immunohistochemistry, western blot and RT-PCR, respectively. Morphologic change of tight junction was also observed in different kinds of endometria
  
  
  RESULTS
  (1) Glandular epithelial cells of control endometrium and eutopic endometrium showed intact tight junctions in electron micrographs, whereas the morphology of tight junctions in ovarian endometriotic tissue was disrupted and collagen bundles could be easily detected. (2) The immunohistochemical staining of claudin-4 was localized to the glandular epithelial cell membrane. Deficient or weak staining was found in ovarian endometriotic tissues. In control endometrium, eutopic and ectopic endometrium of women with endometriosis, the expression of claudin-4 protein was 89 +/- 24, 84 +/- 22 and 27 +/- 14, respectively. Relative expression of claudin-4 mRNA was 14.5 +/- 6.8, 13.8 +/- 9.5 and 2.6 +/- 2.5, respectively. Expression of claudin-4 was significantly lower in the ectopic endometriotic tissue than in the eutopic endometrium and the control at both mRNA and protein levels (P<0.05). No significant difference was found between eutopic endometrium from women with endometriosis and control endometrium from women without endometriosis (P>0.05).
  
  
  CONCLUSIONS
  Down-regulated expression of claudin-4 might play a pathogenic role in the formation of endometriosis.
authors.affiliation: Department of Obstetrics and Gynecology, Qilu Hospital, Shandong University, Jinan 250012, China. changpanxiaoyu@163.com
authors.forename: Xiao-yu
authors.initials: XY
authors.lastname: Pan
authors.forename: Zhan-ping
authors.initials: ZP
authors.lastname: Weng
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002828:Choristoma / Q000378:metabolism / Q000473:pathology; D062506:Claudin-4; D004715:Endometriosis / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D004717:Endometrium / Q000378:metabolism* / Q000473:pathology*; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012720:Severity of Illness Index; D019108:Tight Junctions / Q000473:pathology
chemical_list: C568157:CLDN4 protein, human; D062506:Claudin-4; D008565:Membrane Proteins; D012333:RNA, Messenger