Effect of interval-training exercise on subchondral bone in a chemically-induced osteoarthritis model.
OBJECTIVES
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.


CONCLUSION
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.
['Boudenot|A|A|', 'Presle|N|N|', 'Uzbekov|R|R|', 'Toumi|H|H|', 'Pallu|S|S|', 'Lespessailles|E|E|']
D015502:Absorptiometry, Photon D000818:Animals D001169:Arthritis, Experimental D015519:Bone Density D002358:Cartilage, Articular D004195:Disease Models, Animal D004791:Enzyme Inhibitors D019807:Iodoacetic Acid D008297:Male D010003:Osteoarthritis D010011:Osteocytes D010805:Physical Conditioning, Animal D051381:Rats D017208:Rats, Wistar D055114:X-Ray Microtomography
Interval-training Subchondral bone Osteoarthritis Knee Bone mineral density Microarchitecture