Figure 5.

Effect of THIK-1 Knockout on Microglial Surveillance, Morphology, and Density, In Vivo

(A) Specimen images taken 5 min apart in vivo of WT (P23) and THIK-1 KO Iba1-GFP (P22) microglia, showing process extensions and retractions (colors as in Figure 1A) and the less ramified shape of microglia in the KO.

(B) Quantification of surveillance for microglia from P21–P27 WT and KO mice, showing less surveillance in the KO.

(C) Time course of increase of the number of surveyed pixels in maximum-intensity projections of images of microglia (as in Movie S5, numbers of cells on bars in D) in WT and KO Iba1-GFP mice aged P21–P27. Initial value is the area of the cell in the first image frame.

(D) Initial slope of graphs in (C) (measured over the first 2 min, when assessment of surveillance is least confounded by pixel overlap in the maximum-intensity projection).

(E) Specimen images of perfusion-fixed WT and THIK-1 KO hippocampal slices labeled for Iba1 show that microglial density and tiling appear unchanged in the KO.

(F) Microglial density in the strata radiatum and lacunosum-moleculare of areas CA1-CA3 of 12 WT and 12 KO hippocampal slices (from 3 WT and 3 KO animals at P20–P27).

(G–I) Ramification analysis of P17–P21 microglia from perfusion-fixed WT and THIK-1 KO mice showing (G) representative 3D-reconstructed WT and KO microglia, and (H and I) Sholl analysis-derived number of processes (H) and number of process intersections with shells at distances (in 1 μm increments) from the soma (I).

(J–L) Ramification analysis (as in G–I) of microglia in perfusion-fixed P12 rats that had been anaesthetised for 1 hr either with isoflurane or urethane. p values in (I) and (L) compare distributions (using two-way ANOVA). Data are represented as mean ± SEM. See also Figures S2 and S5.