Figure 1

Development of punctate (A) and dynamic (B) allodynia and weight bearing deficit (C) following intraarticular injection of monosodium iodoacetate (MIA, 2 mg; ■) MIA or saline (○) in the right knee. (A) Baseline (BL) paw withdrawal thresholds (PWT) were determined in both hind paws prior to injection. PWT to von Frey hair stimulation of the plantar paw surface were assessed on various days post-injection. Results are expressed as median force (g) required for a paw withdrawal in 10 animals per group (vertical bars represent first and third quartiles). * P < 0.05, ** P < 0.01, *** P < 0.001 significantly different (Mann-Whitney U test) from saline-treated group at each time point. (B) Baseline (BL) paw withdrawal latencies (PWL) to stroking the plantar paw surface with a cotton bud were determined for both hind paws prior to injection. Results are expressed as mean PWL (s) in 10 animals per group (vertical bars represent ± SEM). * P < 0.05, ** P < 0.01, *** P < 0.001 significantly different (one-way ANOVA followed by Dunnett's posthoc test) from saline-treated group. (C) Baseline (BL) hind paw weight distribution was determined prior to injection. Changes in hind paw weight distribution were assessed on various days post-injection. Results are expressed as mean change in weight distribution (contralateral-ipsilateral) (g) in 10 animals per group (vertical bars represent ± SEM). * P < 0.05, ** P < 0.01, *** P < 0.001 significantly different (one-way ANOVA followed by Dunnett's posthoc test) from saline-treated group. Reprinted from [46], Copyright 2004, with permission from Elsevier.