title: Inhibition of cartilage degradation and suppression of PGE2and MMPs expression by pomegranate fruit extract in a model of posttraumatic osteoarthritis.
abstract: OBJECTIVE
  Osteoarthritis (OA) is characterized by cartilage degradation in the affected joints. Pomegranate fruit extract (PFE) inhibits cartilage degradation in vitro. The aim of this study was to determine whether oral consumption of PFE inhibits disease progression in rabbits with surgically induced OA.
  
  
  METHODS
  OA was surgically induced in the tibiofemoral joints of adult New Zealand White rabbits. In one group, animals were fed PFE in water for 8 wk postsurgery. In the second group, animals were fed PFE for 2 wk before surgery and for 8 wk postsurgery. Histologic assessment and scoring of the cartilage was per Osteoarthritis Research Society International guidelines. Gene expression and matrix metalloproteinases (MMP) activity were determined using quantitative reverse transcriptase polymerase chain reaction and fluorometric assay, respectively. Interleukin (IL)-1 β, MMP-13, IL-6, prostaglandin (PG)E2, and type II collagen (COL2A1) levels in synovial fluid/plasma/culture media were quantified using enzyme-linked immunosorbent assay. Expression of active caspase-3 and poly (ADP-ribose) polymerase p85 was determined by immunohistochemistry. Effect of PFE and inhibitors of MMP-13, mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB was studied in IL-1 β-stimulated rabbit articular chondrocytes.
  
  
  RESULTS
  Safranin-O-staining and chondrocyte cluster formation was significantly reduced in the anterior cruciate ligament transaction plus PFE fed groups. Expression of MMP-3, MMP-9, and MMP-13 mRNA was higher in the cartilage of rabbits given water alone but was significantly lower in the animals fed PFE. PFE-fed rabbits had lower IL-6, MMP-13, and PGE2levels in the synovial fluid and plasma, respectively, and showed higher expression of aggrecan and COL2A1 mRNA. Significantly higher numbers of chondrocytes were positive for markers of apoptosis in the joints of rabbits with OA given water only compared with those in the PFE-fed groups. PFE pretreatment significantly reduced IL-1 β induced IL-6 and MMPs expression in rabbit articular chondrocytes. These effects were also mimicked using MMP-13, MAPK, and NF-κB inhibitors in IL-1 β-stimulated rabbit chondrocytes. In an in vitro activity assay, PFE blocked the activity of MMP-13. Like MAPK and NF-κB inhibitors, PFE was also effective in inhibiting IL-1 β-induced PGE2production in rabbit chondrocytes. PFE also reversed the inhibitory effect of IL-1β on COL2A1 mRNA and protein expression in IL-1 β-stimulated rabbit chondrocytes.
  
  
  CONCLUSIONS
  The present data highlight the chondroprotective effects of PFE oral consumption in a model of posttraumatic OA and suggest that PFE-derived compounds may have potential value in the management of OA.
authors.affiliation: Department of Anatomy & Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio; Department of Pharmaceutical Sciences, College of Pharmacy, Washington State University, Spokane, Washington.
authors.forename: Nahid
authors.initials: N
authors.lastname: Akhtar
authors.affiliation: Department of Anatomy & Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio.
authors.forename: Nazir M
authors.initials: NM
authors.lastname: Khan
authors.affiliation: Department of Anatomy & Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio.
authors.forename: Omer S
authors.initials: OS
authors.lastname: Ashruf
authors.affiliation: Department of Anatomy & Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio. Electronic address: thaqqi@neomed.edu.
authors.forename: Tariq M
authors.initials: TM
authors.lastname: Haqqi
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D017209:Apoptosis; D002356:Cartilage / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D024043:Collagen Type II / Q000235:genetics / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism*; D004195:Disease Models, Animal; D018450:Disease Progression; D005260:Female; D005638:Fruit; D007378:Interleukins / Q000378:metabolism; D007596:Joints / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D029561:Lythraceae; D008297:Male; D045726:Metalloproteases / Q000235:genetics / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D010003:Osteoarthritis / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D013582:Synovial Fluid / Q000378:metabolism
chemical_list: D024043:Collagen Type II; D007378:Interleukins; D016328:NF-kappa B; D010936:Plant Extracts; D012333:RNA, Messenger; D020928:Mitogen-Activated Protein Kinases; D045726:Metalloproteases; D015232:Dinoprostone
keywords: ACLT; MMPs; Osteoarthritis; PGE(2); Pomegranate; Rabbit