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. 2014 Jan 20;5:3125. doi: 10.1038/ncomms4125

Figure 7. Neurogenic inflammation and pain by LPS depend on TRPA1 activity.

Figure 7

(a) Trinitrophenol (TNP, 50 μM) and LPS (100 μg ml−1) evoke (mean±s.e.m.) modest but significant (#P<0.05, Wilcoxon test, n=12/8) tracheal CGRP release; preincubation with TNP potentiates response to LPS and acrolein (30 μM). Trpa1 KO mice do not respond to LPS (*P<0.05, analysis of variance (ANOVA) Fisher’s least significant difference (LSD) test, n=4), TNP or its co-application with LPS or acrolein (**P<0.01). (ANOVA Fisher’s LSD test, n=8, 4, 4). (b) LPS and 4-hydroxy-2-nonenal (HNE) evoke small but significant (#P<0.05) CGRP responses. Preincubation with low concentration of HNE potentiates tracheal CGRP release evoked by LPS (**P<0.01, ANOVA Fisher’s LSD test, n=4, mean±s.e.m.). (c) Summary of effect of LPS (100 μg ml−1) perfusion on mesenteric artery diameter (mean±s.e.m.) from WT (n=7) and Trpa1 KO (n=8) mice in control condition and in the presence of HC-030031 (10 μM). Arteries precontracted with the alpha1 adrenergic agonist phenylephrine (2 μM). Statistical differences were evaluated with an unpaired t-test. (d) The nocifensive response and the acute local inflammation produced by intraplantar LPS injection (5 μg μl−1 in 10 μl) were nearly abolished in Trpa1 KO animals (n=6) compared with WT littermates (n=7) (unpaired t-test, values are mean±s.e.m.). (e) Mechanical paw withdrawal threshold (mean±s.e.m.) to mechanical stimulation before and after intraplantar injection of LPS (5 μg μl−1) in WT (n=14) and Trpa1 KO (n=14) animals. The asterisks reflect the differences in threshold between WT and KO (unpaired t-test). Comparison between baseline and the different time points gave significant differences (##P<0.01, ###P<0.001) in WT animals only (one-way ANOVA with Bonferroni’s correction). (f) Correlation between the hind paw inflammation (mean±s.e.m.) induced by LPSs of different shapes (blue for cylindrical, red for semiconical and black for conical; n=5–9) with the potency for TRPA1 activation (mean±s.e.m.) estimated from the amplitude of Ca2+ response evoked in mTRPA1 cells; Fig. 5d).