Figure 2.

Conditioned medium from Mecp2-null microglia caused damage to dendrites. wt hippocampal neurons, at least 14 d in vitro, were incubated with 50% conditioned media from wt microglia (wt MCM) or null microglia (null MCM) for 24 h. A, Representative phase contrast images and immunofluorescent images in which the dendrites were demonstrated by immunostaining for MAP2 (red) and Ac-TN (green). B, Sparsely plated neurons immunostained for MAP2. Shown are examples of neurons damaged by null MCM showing stunted dendritic morphology and frequent beaded appearance (arrows). C, NeuN-immunoreactive neurons in each treatment condition were counted and averaged from three independent experiments to demonstrate that neuronal viability was not affected by MCM treatment or the drug treatment shown in Figures 3 and 5. The drugs shown here are glutaminase inhibitor DON, to reduce the glutamate production by microglia, and glutamate receptor antagonists MK801 and NBQX, to block the neuronal action of glutamate.