Fig. 2

Tactile sensitivity before and after intra-articular injection of IDO-Gal3 or saline in MCLT + MMT operated knees. The 50% paw withdrawal threshold in MCLT + MMT operated limbs decreased at week 5 and week 7 relative to week 0 (^, p < 0.05), indicating a heightened sensitivity to touch caused by MCLT + MMT surgery. Following intra-articular injections, 50% paw withdrawal thresholds increased in both saline- and IDO-Gal3-treated animals relative to pretreatment (#, p < 0.05), with 6 of 7 rats returning to baseline sensitivity levels in the IDO-Gal3 group by week 9. The average tactile sensitivity for IDO-Gal3- and saline-treated animals did not vary after treatment; however, when change in tactile sensitivity relative to each animal’s week 7 value was assessed (paired analysis), increases in tactile sensitivity in IDO-Gal3-treated animals were larger than saline-treated animals at weeks 9–11 (p ≤ 0.041, Fig. 2B). As Chaplan’s up-down protocol provides a discrete set of data, results are shown as box plots with median, 25–75% interquartile range, and the lower and upper fence. Data outside the fence are plotted as individual data points