Figure 4

ATF3 expression increases in mouse L3 and L4 DRG neurons after SNI, but not L5. (A) Representative immunofluorescence showing that ATF3 (marker of injured neurons, red) was mostly up-regulated in L3 and L4 DRG neurons (HuD positive cells, green) after SNI. Scale bar = 50 μm. (B) Quantification of ATF3-immunoreactivity (IR) in L3, L4 and L5 DRG neurons one week after SNI or sham surgery. ATF3-IR was higher in L3 and L4 after SNI, but remained the same in L5 DRG. Data are expressed as mean ± SEM, n = 4 animals in each group. ***p < 0.001, two-way ANOVA and post hoc Bonferroni tests. (C) mRNA levels of ATF3 one week after SNI compared to sham surgery in L3, L4 and L5 DRG. ATF3 mRNA was higher in L3 and L4 after SNI, but not in L5. Levels of transcripts were first normalized to GAPDH as a reference gene, and then to sham for each DRG. Data are expressed as mean ± SEM, n = 3–4 animals in each group. ***p < 0.001, two-way ANOVA and post hoc Bonferroni tests. SNI, Spared Nerve Injury.