Fig. 3.

Increased nitration and inactivation of manganese superoxide (MnSOD) in peripheral nerve sensory axons (PNSAs) with paclitaxel-treatment; prevention with Mn(III) 5,10,15,20-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (MnTE-2-PyP⁵⁺). Treatment with paclitaxel (Pac) (black bars), but not vehicle (Veh) (open bars), resulted in the development of mechano-allodynia (A) and mechano-hyperalgesia (B) on day (D)25 compared with D0 and was prevented by daily (D0–16) injections of 10 mg/kg/d MnTE-2-PyP⁵⁺ (gray bars) (A,B). At peak hypersensitivity, a significant increase in the nitration of MnSOD (C) and an associated decrease in its activity (D) were observed in the PNSAs of paclitaxel-treated animals compared with vehicle; treatment with MnTE-2-PyP⁵⁺ prevented this (C,D). Representative blots are shown above the quantitative bar graph corresponding to mean ± SD for an n = 4/group (C). Results are expressed as mean ± SD, n = 4–6, and analyzed by one-way analysis of variance (ANOVA) with Dunnett’s post-hoc comparisons or two-way ANOVA with Bonferroni’s post-hoc comparisons. *P < .001 (t_day vs t_{day 0}); ^†P < .001 (Pac + MnTE vs Pac). PWT = paw withdrawal threshold.