Figure 4

Activation of TLR4 in the spinal dorsal horn is critically implicated in the paclitaxel-induced acute allodynia. (A): Line plots show summaries of the mechanical thresholds of hind paw withdrawal responses (mean ± S.E.) in 4 groups of rats. Baseline indicates the baseline measurement before animals received any treatments. Taxol (2 mg/kg) or vehicle was given to rats through the tail vein. LPS-RS or saline was applied into the lumbar enlargement through an intrathecal catheter immediately before and at 3 h after i.v. injection of taxol or vehicle. Comparisons between baseline and at each time point are indicated with v for the IV Taxol + IT saline group. Comparisons between the IV Taxol + IT saline group and the IV Taxol + IT LPS-RS group are labeled with *. Comparisons between the IV Taxol + IT saline group and the IV vehicle + IT LPS-RS group are labeled with #. Comparisons between the IV taxol + IT saline group and the IV vehicle + IT saline group are labeled with +. (B): Line plots show summaries of the mechanical thresholds of hind paw withdrawal responses (mean ± S.E.) in 4 groups of mice. Taxol (2 mg/kg) or vehicle was injected to mice intraperitoneally. Comparisons between baseline and at each time point are indicated with ^ for the C57BL/6J (wild-type) + Taxol group. Comparisons between the C57BL/6J + Taxol group and the C57BL/6J + vehicle group are labeled with +. Comparisons between the C57BL/6J + Taxol group and the TLR4 Knockout (KO) + taxol group are labeled with *. Comparisons between the TLR4 Knockout (KO) + vehicle group and the C57BL/6J+ taxol group are labeled with #. One symbol: P < 0.05; Two symbols: P < 0.01; Three symbols: P < 0.001.