Fig. 3From: A bivalent compound targeting CCR5 and the mu opioid receptor treats inflammatory arthritis pain in mice without inducing pharmacologic toleranceMCC22 is effective in the setting of inflammation, has an accumulative effect, and depends on the 22-atom spacer length. a Six- to 8-week-old K/B.g7 arthritic mice were treated with MCC22 once daily (8 μmol/kg/dose). The baseline mechanical pain threshold was recorded each day. The drug was then administered, and the pain threshold was determined again 2 h later. b K/B.g7 arthritic mice that received saline injections showed no increase in mechanical pain threshold. c. Nonarthritic control B6.g7 mice have higher baseline mechanical pain thresholds than K/B.g7 mice (compare with panels a and b) and this is not increased by MCC22 (dosed as in panel a). Data were analyzed using two-way repeated-measures ANOVA with post-hoc Sidak’s multiple comparisons test. Data are displayed as mean ± SEM; n = 4–5 mice/group. d Arthritic K/B.g7 mice received MCC22 or vehicle once daily starting at 6 weeks of age. MCC22 did not affect arthritis severity or ankle thickness. Data are representative of three experiments with a total of 11–13 mice/group and are displayed as mean ± SD. e Histopathologic scoring of ankle inflammation, fibroplasia, and cartilage damage following treatment with vehicle or MCC22. Circles indicate individual mice, bars indicate mean ± SD. *p < 0.05, **p < 0.01Back to article page