Intraganglionic AAV5-CCL2 injection increases the number of macrophages in the DRGs and enhances neurite outgrowth. A, B, Representative images of Iba1 staining in L5 DRG sections obtained 7, 14, and 28 d after intraganglionic injection of AAV5-GFP (A) or AAV5-CCL2 (B). Scale bars, 50 μm. C, A quantification graph comparing the mean number of Iba1-positive macrophages in DRGs injected with AAV5-GFP or AAV5-CCL2. N = 4 animals per group. *p < 0.05 and ***p < 0.001, respectively, by unpaired t test. D, Representative images of DRG sections stained with neurofilament (NF; green) and Iba1 (red) 28 d after intraganglionic injection of AAV5-CCL2. Scale bars, 50 μm. E, Representative images of neurons cultured from L5 DRGs freshly dissected from animals subjected 28 d previously to intraganglionic injection of AAV5-GFP or AAV5-CCL2. The culture period was 15 h and DRG neurons and their neurites were visualized by immunofluorescence staining for β III tubulin. Scale bars, 100 μm. F, A quantification graph comparing the mean neurite length. ***p < 0.001 by unpaired t test.