Effects of complete Freund’s adjuvant (CFA), formalin, or respective controls on paw width, body weight and mechanical sensitivity. The abscissae for all panels is hours or days following bilateral 100 ul injection of CFA (gray bars, Panels A, C, E), formalin (filled bars, Panels B, D, F), or respective saline controls (open bars, all panels). Bars above “BL” show baseline data before injection. Ordinates (Panels A, B): paw width in mm. Ordinates (Panels C, D): body weight in grams. Ordinates (Panels E, F): paw withdrawal threshold from von Frey filaments in grams (log scale). Dollar signs ($) indicate a significant within-group difference from the respective baseline, and asterisks (*) indicate a significant between-group difference at a given time point, as determined by a significant two-way Repeated Measures ANOVA followed by the Holm-Sidak post hoc test (p < 0.05). All points show mean ± SEM from 8 rats. See Additional file 1 for detailed statistical results.