Fig. 6: LIA is a robust method for pain relief in rodents, more effective than conventionally used analgesics. | Nature Communications

Fig. 6: LIA is a robust method for pain relief in rodents, more effective than conventionally used analgesics.

From: Light-induced analgesia provides a drug-free optical method for pain relief via activation of TRAAK k+ channels

Fig. 6: LIA is a robust method for pain relief in rodents, more effective than conventionally used analgesics.

a Diagram explaining the experimental timeline of b and c (created in BioRender). b, c Analgesic effect of LIA (10 min 365 nm illumination of the paw) in 2 chronic pain contexts: wild-type mice with a spared nerve injury (b), and Trek1-Trek2 KO mice (c). Mechanical sensitivity was quantified through von Frey withdrawal threshold. A two-sided Mann–Whitney (b—p = 0.002) or two-sided Wilcoxon’s signed rank test (c—p = 0.0107) was used to compare pre and post-LIA von Frey withdrawal thresholds (*p < 0.05, **p < 0.01). d Diagram explaining the experimental timelines of figures (e–i). IP = intraperitoneal (created in BioRender). e Time course of the analgesic effect of LIA (10 min 365 nm illumination of the paw) on wild-type rats, quantified through von Frey withdrawal threshold. f, g Time course of the analgesic effect of Emla cream application (f) or ibuprofen injection (g) on wild-type mice, quantified through von Frey withdrawal threshold. For ease of comparison to LIA, von Frey withdrawal threshold evolution following LIA treatment on wild-type mice from Fig. 1f is represented in dashed magenta line. h Time course of the analgesic effect of LIA (10 min 365 nm illumination of the paw) on the Trek1−/−-Trek2−/− KO mice chronic pain model. i Time course of the analgesic effects of Emla cream application and ibuprofen injection on Trek1−/−-Trek2−/− KO mice, quantified through von Frey withdrawal threshold. For ease of comparison to LIA, von Frey withdrawal threshold evolution following LIA treatment on Trek1−/−-Trek2−/− KO mice from (h) is represented in dashed magenta line. In (e–i), statistical analyses were carried out on each paw series independently and compare the von Frey withdrawal threshold at each time point to that at the beginning of the experiment (pre-treatment time point) using a Friedman test followed by Dunn’s two-sided multiple comparison test (*p < 0.05, **p < 0.01 – For e: LIA-treated paws: post-LIA: p = 0.0187, 1 h: p = 0.0356, 3 h: p = 0.4155, 6 h: p = 0.3084, non-treated paws: Friedman test: p = 0.0568, for (f): Emla-treated paws: post-Emla: p = 0.1312, 1 h: p = 0.7158, 3 h: p > 0.9999, 6 h: p = 0.8236, non-treated paws: Friedman test: p = 0.5325, for (g): Friedman test: p = 0.3389, for (h): LIA-treated paws: post-LIA: p = 0.0107, 1 h: p = 0.0048, 3 h: p > 0.9999, 6 h: p > 0.9999, non-treated paws: Friedman test: p = 0.5861, for (i): Emla-treated paws: post-Emla: p = 0.0046, 1 h: p = 0.3587, 3 h: p > 0.9999, 6 h: p > 0.9999, Ibuprofen-treated paws: post-ibuprofen: p = 0.0119, 1 h: p = 0.264, 3 h: p > 0.9999, 6 h: p > 0.9999, non-treated paws: Friedman test: p = 0.3696). Animal diagrams in (e–i) were obtained from BioRender. Data shown are mean ± s.e.m. The number of paws used in each experiment is indicated on the figure. Source data are provided in the Source Data file.

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