Fig. 4

DS-SILY prevents monocyte entry to the ONH. a, b and c 1 μg/g [body weight] LPS delivered by intraperitoneal injection is sufficient to drive monocyte entry into the ONH of young, non-diseased B6 mice after 21 days (a, red bars). To prevent monocyte entry into the ONH DS-SILY was administered by three different routes; DS-SILY was protective when administered by an intravenous route, (a, purple bars) in a dose dependent manner (b). Although administration by IP had similar potency to IV, its effects were less long-lasting, lasting; IV lasted > 21 days; IP only 3–5 days (not shown) (n = 4 for all route testing conditions, n > 6 for all concentration testing conditions). DS-SILY administered at 1 μM was used as a sham control (blue bars in a, b and c). c Further testing in young D2 mice determined that DS-SILY was most potent at 25 μM (n = 11 LPS only; 9 DS-SILY only; 23 DS-SILY 10 μM; 8 DS-SILY 25 μM). d Subsequently 25 μM DS-SILY was administered every 21 days via intravenous injection to the tail vein of D2 mice starting at 6–7 mo of age. Mice administered DS-SILY and saline sham controls were harvested at 10.5 mo and ONHs assessed for monocyte entry by flow cytometry. DS-SILY robustly protected from CD45^hi/CD11b⁺/CD11c⁺ monocyte entry (n = 24 saline; 23 DS-SILY). e A subset of monocytes that still entered in DS-SILY treated ONHs were still platelet positive (n = 2 pools of 4 ONHs each). f Example flow plots are shown for (d). CD11b⁺/CD45⁺ = myeloid-derived cells (i.e. microglia and monocytes in the ONH), CD11b⁺/CD45^hi = all monocytes, CD11b⁺/CD45^hi/CD11c⁺ = infiltrating monocyte-like cells, CD11b⁺/CD45^hi/CD11c⁺/CD41⁺ = infiltrating monocyte-like cells that are platelet bound (i.e. monocyte-platelet aggregates)