Fig. 7

Deletion of microglial CX3CR1 in MPTP mice leads to over-induction of astrocytic CCL2 in the affected substantia nigra. a–d Immunohistochemistry with anti-CCL2 antibodies (arrows, brown) shows enhanced induction of CCL2 in the MPTP-affected SNpc of CX3CR1 deleted mice (CX3CR1 ^−/−) (d) as compared to wild-type littermate controls (CX3CR1 ^+/+) (c) (24 h after intoxication; see insets for enlargements). No CCL2 induction was seen in saline control animals (a, b). e Quantification of increased numbers of CCL2 expressing cells within the MPTP-affected SNpc in CX3CR1 ^−/− mice (n = 5) as compared to CX3CR1 ^+/+ littermate controls (n = 6), measured at 24 h after intoxication. Counts represent the estimated total cells within the entire SNpc (individual mice are shown; red bars, mean; quantification, *P = 0.019, Holm-Sidak method). f–k Immunofluorescence stains of MPTP-affected SNpc 24 h after intoxication, showing that in CX3CR1 deleted mice, CCL2 induction (f, i; red, arrows) still colocalized with astrocytes (g; GFAP, green, arrows; with confocal view in h) and remained absent from microglia (j; Iba1, green, arrowheads; with confocal view in k). (Scale bars; d, 100 μm; insets, 20 μm; h and k, 20 μm)