Characterization of the Rat MIA Model of Osteoarthritis in Support of the NIH PSPP Program

Adult male and female Sprague Dawley rats (n=10, each sex) were used in these studies. For the MIA model, MIA (1 – 4.5 mg) was injected intraarticularly into the left hindlimb knee joint. Behavioral pain endpoints included examination of hind paw mechanical allodynia, knee joint mechanical allodynia and dynamic weight bearing deficits. Behavioral pain phenotype in these studies was evaluated for 4-6 weeks following the induction of osteoarthritis. Pharmacology was examined by evaluating dose-dependent effects of the reference analgesics morphine sulfate (0.3 – 6 mg/kg, SC), ketoprofen (0.3 – 6 mg/kg, PO), celecoxib (3 – 30 mg/kg, PO), gabapentin (10 – 100 mg/kg, PO, pregabalin (10 – 60 mg/kg, PO) and duloxetine (3 – 60 mg/kg, PO). Effects of reference analgesics on hind paw mechanical allodynia and dynamic weight bearing deficits were determined following single and repeated administration during Week 1. Data were analyzed using two-way repeated measures ANOVA with Bonferroni’s or