title: Effect of interval-training exercise on subchondral bone in a chemically-induced osteoarthritis model.
abstract: OBJECTIVE
  The role of subchondral bone in osteoarthritis (OA) development is well admitted. Cross-talk between subchondral bone and cartilage may be disrupted in OA, leading to altered subchondral bone remodeling. Osteocytes are involved in bone remodeling control and could play a key role in OA progression. Our purpose of this study was to evaluate the preventive effect of interval-training exercise on subchondral bone and osteocyte in monosodium iodoacetate (MIA) model of experimental OA.
  
  
  METHODS
  At baseline, 48 male Wistar rats (8 weeks old) were separated into two groups: interval-training exercise or no exercise for 10 weeks. After this training period, each group was divided into two subgroups: MIA-injected knee (1 mg/100 μl saline) and saline-injected knee. Four weeks later, rats were sacrificed and carefully dissected. Evaluated parameters were: cartilage degeneration by OA scoring, bone mineral density (BMD) by Dual energy X-ray Absorptiometry (DXA), trabecular subchondral bone microarchitecture by micro-computed tomography (μCT), cortical subchondral bone lacunar osteocyte occupancy (by Toluidine Blue staining) and cleaved caspase-3 positive apoptosis (by epifluorescence).
  
  
  RESULTS
  Our results showed deleterious effects of MIA on cartilage. OA induced a decrease in proximal tibia (PT) BMD which was prevented by exercise. Exercise induced increase in full osteocyte lacunae surface and osteocyte occupancy (+60%) of cortical subchondral bone independently of OA. Osteocyte apoptosis (<1%) in cortical subchondral bone was not different whatever the group at sacrifice.
  
  
  CONCLUSIONS
  Our results suggest that preliminary interval-training improved BMD and osteocytes lacunar occupancy in subchondral bone. Our interval-training did not prevent MIA-induced cartilage degeneration.
authors.affiliation: EA 4708 I3MTO, University of Orléans, Orléans, France. Electronic address: arnaud.boudenot@yahoo.fr.
authors.forename: A
authors.initials: A
authors.lastname: Boudenot
authors.affiliation: UMR 7365 CNRS, Universite de Lorraine, Vandoeuvre-les-Nancy, France.
authors.forename: N
authors.initials: N
authors.lastname: Presle
authors.affiliation: Department of Microscopy, University of Francois Rabelais, Tours, France.
authors.forename: R
authors.initials: R
authors.lastname: Uzbekov
authors.affiliation: EA 4708 I3MTO, University of Orléans, Orléans, France.
authors.forename: H
authors.initials: H
authors.lastname: Toumi
authors.affiliation: EA 4708 I3MTO, University of Orléans, Orléans, France.
authors.forename: S
authors.initials: S
authors.lastname: Pallu
authors.affiliation: EA 4708 I3MTO, University of Orléans, Orléans, France; Service de rhumatologie, Centre hospitalier régional d'Orléans, Orléans, France.
authors.forename: E
authors.initials: E
authors.lastname: Lespessailles
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D001169:Arthritis, Experimental / Q000139:chemically induced / Q000517:prevention & control*; D015519:Bone Density; D002358:Cartilage, Articular / Q000473:pathology*; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000633:toxicity; D019807:Iodoacetic Acid / Q000633:toxicity; D008297:Male; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000473:pathology / Q000517:prevention & control*; D010011:Osteocytes; D010805:Physical Conditioning, Animal / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D055114:X-Ray Microtomography
chemical_list: D004791:Enzyme Inhibitors; D019807:Iodoacetic Acid
keywords: Bone mineral density; Interval-training; Knee; Microarchitecture; Osteoarthritis; Subchondral bone