Quercetin Reduces Ehrlich Tumor-Induced Cancer Pain in Mice

Figure 7

The opioid receptor antagonist, naloxone, inhibits quercetin analgesia in the Ehrlich tumor-induced pain model. Mice were treated with quercetin (100 mg/kg, i.p., starting 10 min after tumor administration) during 8 days after the injection of Ehrlich tumor cells (1 × 10⁶ or 1 × 10⁷ cells/25 μL) or saline and, in the 8th day, one group of mice that received quercetin was also treated with naloxone (1 mg/kg i.p. diluted in saline) 1 h before the treatment with quercetin. The evaluation of mechanical hyperalgesia (a), thermal hyperalgesia (b), and paw thickness (c) was performed 1, 3, 5, and 7 h after the treatments, and the overt pain-like behavior (d) was evaluated 1 h after the treatment. Data are presented as means ± SEM of six mice per group per experiment and representative of two separated experiments: compared to the saline group, compared to the tumor group, and compared to the quercetin group. One-way ANOVA followed by Tukey’s test.

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