Co-localization of BDNF and TNFR1 in the L3-L5 DRGs. Immunoreactivity was detected by double immunofluorescent stain. L3-L5 DRGs were collected after CFA injection for 72 hours. BDNF is shown by green fluorescence and TNFR1 is shown by red fluorescence. (A) Bar graph representing quantitative measurement of numbers of cells displaying TNFR1 and BDNF co-localization. Data are expressed as mean ± SEM and were analyzed using an un-paired Student's t-test. ***p < 0.001 (N = 9 per group); compared to control. (B-D) Photomicrographs illustrate the immunoreactivity of BDNF (B) and TNFR1 (C) in the L3 DRG sections of control group. (D) Merged image of (B) and (C). (E-G) Photomicrographs illustrate the immunoreactivity of BDNF (E) and TNFR1 (F) in L3 DRG sections of the CFA group. (G) Merged image of (E) and (F). Inserts illustrate BDNF and TNFR1 signals that co-localized in a DRG neuron. Wide arrow, co-localized BDNF and TNFR1; narrow arrow, TNFR1; arrowhead, BDNF. Scale bars, 50 μm.