title: Expression of peroxisome proliferator-activated receptors α, β, γ, and H- and L-prostaglandin D synthase during osteoarthritis in the spontaneous hartley guinea pig and experimental dog models.
abstract: OBJECTIVE
  To investigate the expression of peroxisome proliferator-activated receptors (PPAR) α, β, and γ, and hematopoietic and lipocalin-type prostaglandin D synthase (H- and L-PGDS) over the course of osteoarthritis (OA) in the spontaneous Hartley guinea pig and the anterior cruciate ligament transection dog models.
  
  
  METHODS
  Guinea pigs were sacrificed at 2 (control group), 4, 8, and 12 months of age (n = 5 per group). Non-operated (control) and operated dogs were sacrificed at 4, 8, and 12 weeks postsurgery. Cartilage was evaluated histologically using the Osteoarthritis Research Society International (OARSI) guidelines. The expression of PPAR-α, β, γ, and H- and L-PGDS was evaluated by real-time PCR and immunohistochemistry. The nonparametric Spearman test was used for correlation analysis.
  
  
  RESULTS
  PPAR-α, β, and γ were detected in medial tibial plateau from control animals in both the spontaneous and surgical models. Levels of PPAR-α and β did not change over the course of OA, whereas PPAR-γ levels decreased during progression of disease. We also observed that the expression of H-PGDS remained unchanged, whereas L-PGDS increased over the course of OA. PPAR-γ levels correlated negatively, whereas L-PGDS levels correlated positively, with the histological score of OA.
  
  
  CONCLUSIONS
  The level of PPAR-γ decreased, whereas level of L-PGDS increased during the progression of OA. These data suggest that reduced expression of PPAR-γ may contribute to the pathogenesis of OA, whereas enhanced expression of L-PGDS may be part of a reparative process.
authors.affiliation: Osteoarthritis Research Unit, University of Montreal Hospital Research Center (CRCHUM), Notre-Dame Hospital, Montréal, Québec, Canada.
authors.forename: Sarah-Salwa
authors.initials: SS
authors.lastname: Nebbaki
authors.forename: Fatima Ezzahra
authors.initials: FE
authors.lastname: El Mansouri
authors.forename: Hassan
authors.initials: H
authors.lastname: Afif
authors.forename: Mohit
authors.initials: M
authors.lastname: Kapoor
authors.forename: Mohamed
authors.initials: M
authors.lastname: Benderdour
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Pelletier
authors.forename: Johanne
authors.initials: J
authors.lastname: Martel-Pelletier
authors.forename: Hassan
authors.initials: H
authors.lastname: Fahmi
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000235:genetics / Q000378:metabolism*; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology; D004285:Dogs; D006168:Guinea Pigs; D019746:Intramolecular Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D007719:Knee Joint / Q000378:metabolism / Q000473:pathology; D054834:Lipocalins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D053509:Matrix Metalloproteinase 13 / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D010003:Osteoarthritis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D047492:Peroxisome Proliferator-Activated Receptors / Q000235:genetics / Q000378:metabolism*
chemical_list: D054834:Lipocalins; D047492:Peroxisome Proliferator-Activated Receptors; D009569:Nitric Oxide; D053509:Matrix Metalloproteinase 13; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase
keywords: CARTILAGE; OSTEOARTHRITIS; PEROXISOME PROLIFERATOR-ACTIVATED RECEPTORS; PROSTAGLANDIN D SYNTHASE