Figure 2.

Neuronal lesioning does not induce peripheral cell migration into the brain: A, IL-1β levels significantly decrease with 70% microglial elimination in 2-month-old wild-type mice (n = 4/group). B–F, An additional cohort of 11 month-old CaM/Tet mice (B57BL/6) had doxycycline withdrawn from the diet for 25 d to induce a neuronal lesion in mice with both transgenes (lesion), and EB was injected on the 25^th day of lesion, 6 h before kill. Single-transgenic mice served as nonlesioning controls (control). B, EB staining was present in the peripheral tissue of all injected mice, but not in the brains of control or lesion mice. C, Quantification of EB absorbance at 595 nm. D, E, Representative flow cytometry analyses for PE-Cy7-CD11b and PE-CD45 in control and lesion mice. Box 1: live cells; Box 2: CD11b⁺ cells; Box 3: CD11b⁺, CD45⁺ cells; Box 4: CD45^lo/mod cells; Box 5: CD45^hi cells. F, Quantification revealed no differences between groups in the percentage of CD11b⁺ cells that were also CD45⁺ (Box 3), nor in the percentage of CD45^hi cells (Box 5). Mean PE intensity of CD45^lo/mod cells was significantly higher in lesion compared with control (two-tailed unpaired t test, p < 0.001; Box 4). G, Twenty times (top row) and 63× (bottom row) representative images show that regardless of experimental group, IBA1⁺ cells (red channel) in the brain did not stain positively for CD169 (green channel). CD169 positively labeled cells in thymus tissue. *p < 0.05, ****p < 0.001. Error bars indicate SEM; n = 3/group.