Fig. 2

Accumulation of activated microglia in the lumbar spinal cord during RCS loading. a–d The appearance and accumulation of activated microglia in the L5 spinal cord along the RCS protocol. Note that a significant accumulation of microglia (Iba1-positive cells) was observed in the medial part of the DH from day 5 of RCS. A slight accumulation of microglia was observed in the VH from day 5 of RCS; this was markedly increased at day 7. The dotted areas, designated 1, 2, and 3 in a, are the areas used for quantification in g. e Higher-magnification images of Iba1-positive microglia in the DH of the L5 spinal cord after 7 days of RCS loading (day 7). The area surrounded by a blue dotted rectangle is magnified in e’. f Magnified images of activated microglia in the VH of the lumbar spinal cord on day 7 of RCS loading. The area surrounded by a blue dotted rectangle is magnified in f’. Note that both e’ and f’ clearly demonstrate that the accumulated microglia have an activated shape. g Quantification of the numbers of microglia in Area 1: medial area of the DH; Area 2: intermediate column; and Area 3: dorsal area of the VH; surrounded by dotted squares in the image in a. n = 5 mice for each group. *p < 0.01, **p < 0.001, ***p < 0.0001. Error bars indicate the SEM. One-way ANOVA with Dunnett's multiple comparisons test. The white dotted lines indicate the edge of spinal cord in a–d and the edge of spinal cord and gray matter in e–f’. Scale bars = 200 μm in e, f, and 50 μm in e’, f’