Figure 3

Liposomic clodronate specifically depletes microglia from hippocampal slice cultures. Untreated mouse hippocampal slice cultures showed preserved organotypic structure with ramified microglia (A, Iba1), astrocytes (B, GFAP) and neuronal layers CA1/CA3/DG (C, Neun). Overnight treatment with liposome-encapsulated clodronate (Lip-CL) directly after slice culture preparation resulted in specific depletion of microglia (D), while astrocytes (E) and neurons (F) remained unaffected. After 6 days in culture, the microglia population in Lip-CL treated slice cultures was reduced to less than 5% (D). Scale bars indicate 300 μM (overviews) and 25 μM (inserts). Confocal images were grey-scaled. (G) qPCR analysis of control- and Lip-CL-treated slice cultures revealed no differences in the levels of β-III-tubulin and GFAP confirming our observation that Lip-CL does not affect the presence of neurons and astrocytes. In comparison, CD11b mRNA levels were strongly reduced in Lip-CL-treated slice cultures, indicating that the number of endogenous microglia left in these slice cultures is really low. Finally, no differences were observed in NR1, NR2A and NR2B subunit mRNA levels, showing that these were not affected by the Lip-CL treatment. Bars indicate mean ± SEM. ***p < 0.001.