Fig. 3

Intensity theory model of nerve injury extent, CSF IL-6 content, and widespread pain. A The schematic diagram of 25%, 50%, 75%, and 100% ligation of infraorbital nerve. B The time course of mechanical escape threshold of vibrissal pad of CCI-ION rats with different degrees of ligation. Two-way ANOVA, ****p < 0.0001, vs. sham, n = 7/group. C-D The paw thermal withdrawal latency and mechanical threshold in CCI-ION rats with different degrees of infraorbital nerve ligation. Two-way ANOVA, ***p < 0.001, ****p < 0.0001, vs. sham, n = 7/group. E ELISA analyzed the concentration of IL-6 in the CSF samples from the sham rats and CCI-ION rats with different degrees of nerve ligation. One-way ANOVA, *p < 0.05, ***p < 0.001, vs. sham, n = 5–7/group. F The sketch of an intensity theory model: the relationship of nerve injury, IL-6 concentration in the CSF and widespread pain