Fig 1: Knockout of netrin-1 abrogates sensory innervation and spinal pain.a Representative images of immunofluorescent analysis of TRAP+ (red), Netrin-1+ (green), and DAPI (blue) staining of nuclei in caudal endplates of L4/5 after LSI or sham surgery. Scale bars, 50 μm. b ELISA analysis of Netrin-1 concentration in the lysate of lumbar endplates after LSI surgery. **p < 0.01 compared with the sham surgery mice. n = 3 per group. c Representative images of immunofluorescent analysis of CGRP+ (red), DCC+ (green), and DAPI (blue) staining of nuclei in caudal endplates of L4/5 after LSI surgery. Scale bars, 50 μm. d Representative images of safranin O and fast green staining of the caudal endplates of L4/5 in Netrin-1−/− or Netrin-1f/f mice after LSI or sham surgery. Scale bars, 50 μm. e Endplate scores of the caudal endplates. f Representative images of TRAP (magenta) staining of the caudal endplates of L4/5 in Netrin-1−/− or Netrin-1f/f mice after LSI or sham surgery. Scale bars, 50 μm. g Quantitative analysis of (f). h Representative images of immunofluorescent analysis of CGRP+ (red) and DAPI (blue) staining of nuclei in caudal endplates of L4/5 in Netrin-1−/− or Netrin-1f/f mice after LSI or sham surgery. Scale bars, 50 μm. i Quantitative analysis of (h). j–p Quantitative analysis of spinal pain-related behavior tests, including pressure hypersensitivity (j), distance traveled (k), maximum speed (l), mean speed (m), active time (n) per 24 h, and hind paw withdrawal frequency responding to mechanical stimulation (0.7 mN; o and 3.9 mN; p) in Netrin-1−/− or Netrin-1f/f mice after LSI or sham surgery. *p < 0.05, **p < 0.01 compared with Netrin-1f/f sham surgery mice, #p < 0.05, ##p < 0.01 compared with Netrin-1f/f LSI surgery mice at the corresponding time points, ns, no significant difference, compared with Netrin-1f/f LSI surgery mice at the corresponding time points. n = 7 per group (g, i–p). Statistical significance was determined by multifactorial ANOVA, and all data are shown as means ± standard deviations. Source data are provided as a Source Data file.