Establishing the Ankle Osteoarthritis Mouse Model

The AOA (Ankle Osteoarthritis) mouse model was established as previously described^{61 (link),62 (link)}. Briefly, 4-month-old C57BL/6 female mice (Jackson Laboratory) were anesthetized and underwent AOA or a sham operation of right paw. Postoperative care consisted of an injection of 5.0 mg/kg carprofen (Rimadyl; Zoetis Inc, Parsippany-Troy Hills, NJ) diluted with saline, time under a warming lamp, and visual monitoring at least once every 24 h for 72 h. A 12.5-mg carprofen tablet was administered for pain management, no additional medication was needed. All animals were maintained at the animal facility of the Johns Hopkins University School of Medicine. We obtained whole blood samples by cardiac puncture immediately after euthanasia. Serum was collected by centrifuge at 1 500 r/min for 15 min and stored at −80°C before analyses. Talus of the mice were also collected.