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. 2017 Apr 10;9(6):802–815. doi: 10.15252/emmm.201607300

Figure 2. The effect of topical borneol on mouse models of pain.

Figure 2

  • A, B
    Quantification of the borneol effect on capsaicin (Cap)‐induced nociceptive responses in mice. 25% of either medical borneol (A) or chemical borneol (B) was applied to a hindpaw for a total of three times at 10‐min intervals, and 100 μM Cap was injected into the paw after 10 min. Paw licking and lifting time was measured within 5 min after Cap injection. Saline was used as a control to Cap, and ethanol was used as a control to borneol.
  • C
    Quantification of the borneol effect on formalin‐induced biphasic pain responses in mice. 0–15% borneol was applied to a hindpaw for a total of three times at 10‐min intervals, and 1.5% formalin was injected into the paw after 10 min. Paw licking and lifting time was measured within the first 5 min (Phase 1) and within 15–60 min (Phase 2).
  • D
    Quantification of the borneol effect on CFA‐induced mechanical hyperalgesia in mice. CFA was injected into a hindpaw, and saline was injected into another hindpaw at day 0. At each experimental day, ethanol (black) or 15% borneol (red) was topically applied to both hindpaws for a total of three times at 10‐min intervals. After 10 min, 50% paw withdrawal thresholds were measured with von Frey filaments in both the ipsilateral (CFA‐injected) and contralateral hindpaws. Ethanol was used as a control to borneol. The statistical analysis was performed between the groups of Ethanol (Ipsilateral) and Ethanol (Contralateral) with the statistical significance indicated by asterisks, or of Borneol (Ipsilateral) and Ethanol (Ipsilateral) with the statistical significance indicated by pound signs. n = 8 mice for each group.
  • E
    Quantification of the borneol effect on CFA‐induced thermal hyperalgesia in mice. Either saline or CFA was injected into both hindpaws at day 0. At each experimental day, ethanol or 15% borneol was applied to both hindpaws for a total of three times at 10‐min intervals. After 10 min, the nociceptive response latencies of mice were measured in a hot plate test (52°C). Saline was used as a control to CFA, and ethanol was used as a control to borneol. The statistical analysis was performed between the groups of Ethanol + CFA (n = 9) and Ethanol + Saline (n = 10) with the statistical significance indicated by asterisks, or of Borneol + CFA (n = 10) and Ethanol + CFA (n = 9) with the statistical significance indicated by pound signs.
Data information: In (A–C), the number of mice is indicated on top of each bar. Statistical significance was evaluated using two‐tailed t‐test (for two‐group comparisons) or one‐way analysis of variance (ANOVA) followed by Tukey's test (for multi‐group comparisons). *P < 0.05; **P < 0.01; ***P < 0.001; # P < 0.05; ## P < 0.01; ### P < 0.001; the exact P‐values are indicated in Appendix Table S1. All the data are presented as the mean ± standard error of the mean (SEM).