title: RNA interference targeting hypoxia inducible factor 1alpha reduces post-operative adhesions in rats.
abstract: BACKGROUND
  To investigate the use of RNA interference mediated gene down-regulation targeting hypoxia inducible factor 1alpha (HIF-1alpha) and plasminogen activator inhibitor 1 (PAI-1) in an effort to prevent abdominal adhesion formation.
  
  
  METHODS
  Real time PCR and a PAI-1 protein activity assay were used in vitro to determine the efficacy of small interfering RNAs (siRNAs). For in vivo experiments, 57 white female rats were operated to generate ischemic and serosal injury to the uterine horns, and treated with saline, siRNA(Lamin A/C) (negative control), siRNA(HIF-1alpha), siRNA(PAI-1), or siRNA(HIF-1alpha) plus siRNA(PAI-1). The cationic polyer poly(ethylenimine) (PEI) was used as the delivery vehicle for all siRNAs delivered in vivo. Adhesions were analyzed by a blinded surgeon 8 days post-surgery.
  
  
  RESULTS
  After in vitro transfection with siRNA, at least 69% gene down-regulation was obtained for all siRNAs tested. In vitro siRNA-mediated down-regulation of HIF-1alpha, PAI-1 or their simultaneous delivery resulted in a significant decrease of PAI-1 protein activity (at least P < 0.05). Administration of 4 nmol siRNA(HIF-1alpha)/PEI complexes after injury to the uterine horns achieved a statistical reduction of post-operative adhesion formation with a reduction by 52% (P < 0.05). Delivery of 4 nmol siRNA(PAI-1)/PEI complexes and the simultaneous delivery of 2 nmol siRNA(HIF-1alpha) plus 2 nmol siRNA(PAI-1), resulted in a reduction of abdominal adhesion by 36% and 42%, respectively, with the reduction being statistically significant when compared directly to the saline control (P < 0.01).
  
  
  CONCLUSIONS
  These data show that administration of siRNA/PEI complexes within the peritoneal cavity can be used to prevent post-operative abdominopelvic adhesions.
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Bioengineering and Institute of Chemical Sciences and Engineering, Lausanne, Switzerland.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Segura
authors.forename: Hugo
authors.initials: H
authors.lastname: Schmokel
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Hubbell
mesh_terms: D000005:Abdomen / Q000601:surgery; D000818:Animals; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000037:antagonists & inhibitors* / Q000235:genetics; D017395:Plasminogen Activator Inhibitor 1 / Q000032:analysis; D011094:Polyethyleneimine / Q000494:pharmacology; D011183:Postoperative Complications / Q000517:prevention & control*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000627:therapeutic use; D051381:Rats; D000267:Tissue Adhesions / Q000517:prevention & control*
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D017395:Plasminogen Activator Inhibitor 1; D034741:RNA, Small Interfering; D011094:Polyethyleneimine