Effects Of Mia-Induced Osteoarthritis On Hind Limb Weight Bearing And Bone Biology Endpoints In Rats With Or Without Access To Running Wheels

Our laboratories have been characterizing the interactions between exercise and pain‐like states in rodents. The present set of experiments characterized the effects of monosodium iodoacetate (MIA) on hind limb weight bearing in rats that were either sedentary or had access to running wheels. Rats were given intra‐articular saline or MIA (3.2 mg) into the left hind knee. Rats were divided into two groups. Group 1 had 24 hr voluntary access to running wheels for 42 consecutive days (21 days acquisition followed by 21 days post‐MIA). Group 2 had no access to running wheels. Weight bearing was measured on post‐MIA days 3, 7, and 21. In sedentary rats, MIA produced shifts onto the uninjured hind limb on PD 3, 7 only. In rats with access to running wheels, MIA produced weight asymmetry on PD 3, 7 and 21. To determine potential causal mechanisms behind the differences between sedentary and exercised rats, ex vivo microCT imaging analysis was performed to assess architectural changes to hind limb distal femur/proximal tibia and knee. Data indicated that MIA runners had greater lateral (but not medial) subchondral total volume loss relative to MIA non‐runners. Data for trabecular region are currently being analyzed. These results suggest that within the specific parameters of this study, voluntary wheel running exacerbated the effects of MIA‐induced OA on both behavioral and bone biology measures.Support or Funding InformationFunded by NIAMS/NIH grant AR054975‐02A1 to G.W.S.