title: Early intervention with Interleukin-1 Receptor Antagonist Protein modulates catabolic microRNA and mRNA expression in cartilage after impact injury.
abstract: OBJECTIVE
  The purpose of this controlled laboratory study was to determine the efficacy of Interleukin-1 Receptor Antagonist Protein (IRAP) treatment as an early intervention strategy by examining the changes in microRNA and mRNA expression in cartilage in an ex-vivo porcine knee joint impact model.
  
  
  METHODS
  Custom impact device was used to create replicable injury ex-vivo to intact porcine knee joint. Injury was caused by dropping a 10 kg weight one time from 1 m directly above the knee in extension. One hour after impact 20 μg/ml IRAP solution was intra-articularly injected. At 8 h post-injury, cartilage samples were harvested for cell viability and genetic expression analysis. Genetic expression of miR-27b, miR-140, miR-125b, ADAMTS-4, ADAMTS-5, MMP-3, IL-1β, and TNF-α were analyzed by RT-PCR. Cell viability image analysis was performed using ImageJ software. Groups were compared by analysis of variance (ANOVA) followed by Tukey's post-hoc test. A P-value <0.05 was considered significant.
  
  
  RESULTS
  At 8 h after IRAP treatment, expressions of ADAMTS-4, ADAMTS-5, MMP-3, IL-1β, and TNF-α in cartilage were significantly down-regulated from injury group (all P < 0.001). MiR-140, miR-125b, and miR-27b expressions were significantly up-regulated after treatment as compared to control and injury groups (all P < 0.001).
  
  
  CONCLUSIONS
  This study demonstrates that IRAP treatment administered during acute phase of cartilage impact injury increases expression levels of miR-140, miR-125b, and miR-27b in cartilage, indicating increased inhibition of their respective matrix-degrading enzymes. Clinically, these findings support the potential of IRAP treatment as an early intervention strategy for the prevention of cartilage degeneration after impact injury.
authors.affiliation: Department of Biomedical Engineering, College of Engineering, University of Miami, Coral Gables, FL, USA. Electronic address: agenemar@gmail.com.
authors.forename: A A
authors.initials: AA
authors.lastname: Genemaras
authors.affiliation: Geriatric Research, Education, and Clinical Center and Research Service, Bruce W. Carter Veterans Affairs Medical Center, Miami, FL, USA. Electronic address: treiner@med.miami.edu.
authors.forename: T
authors.initials: T
authors.lastname: Reiner
authors.affiliation: Department of Biomedical Engineering, College of Engineering, University of Miami, Coral Gables, FL, USA. Electronic address: c.huang@miami.edu.
authors.forename: C-Y
authors.initials: CY
authors.lastname: Huang
authors.affiliation: Department of Biomedical Engineering, College of Engineering, University of Miami, Coral Gables, FL, USA; Department of Orthopedics, Division of Sports Medicine, University of Miami Miller School of Medicine, Miami, FL, USA. Electronic address: kaplan@med.miami.edu.
authors.forename: L
authors.initials: L
authors.lastname: Kaplan
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology; D019902:Chondrocytes / Q000378:metabolism / Q000473:pathology; D010122:Cystinyl Aminopeptidase / Q000494:pharmacology*; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D035683:MicroRNAs / Q000096:biosynthesis / Q000235:genetics*; D010003:Osteoarthritis / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics*; D013552:Swine
chemical_list: D035683:MicroRNAs; D012333:RNA, Messenger; D010122:Cystinyl Aminopeptidase; C105964:leucyl-cystinyl aminopeptidase
keywords: Cartilage; Impact injury; MicroRNA; Post-traumatic osteoarthritis