Fig. 5: C3^−/− mice are protected from stress-induced synapse loss.

A Representative images of VGlut2 (magenta) and PSD95 (green) synapses colocalization in layer 2/3 mPFC from wildtype and C3^−/− control/CORT mice. Circles indicate colocalized pre- and postsynaptic puncta. Scale bar 5 µm. B Representative images of microglial VGlut2 synapse engulfment in layer 2/3 mPFC from wildtype and C3^−/− control/CORT mice. Representative IHC image (left) with corresponding 3D reconstruction (inset, right) showing localization of engulfed VGlut2 (magenta) in CD68-positive lysosomes (blue) in Iba1-positive microglia (green). Scale bar 5 µm for IHC image, scale bar 1 µm for inset. C Quantitation of colocalized VGlut2 & PSD95 synaptic puncta in layer 2/3 mPFC of wildtype and C3^−/− control/CORT mice. Data analyzed by two-way ANOVA, followed by Sidak’s post-hoc test comparing means within genotype. F(1,29) = 4.518, p = 0.0422 (genotype x stress interaction), n = 9 wildtype control, 9 wildtype CORT, 8 C3^−/− control, and 7 C3^−/− CORT, **p 0.0079. Data plotted as mean ± s.e.m. D Quantitation of microglial VGlut2 engulfment in layer 2/3 mPFC of wildtype and C3^−/− mice. Data analyzed by two-way ANOVA, followed by Sidak’s post-hoc test comparing means within genotype, F(1,30) = 12.87, p = 0.0012 (genotype x stress interaction), n = 9 wildtype control, 9 wildtype CORT, 8 C3^−/− control, and 8 C3^−/− CORT, ****p < 0.0001. E Quantitation of colocalized VGlut2 & PSD95 synaptic puncta in layer 5 mPFC of wildtype and C3^−/− control/CORT mice. Data analyzed by two-way ANOVA, F(1,25) = 0.2419, p = 0.6271, n = 8 wildtype control, 7 wildtype CORT, 7 C3^−/− control, and 7 C3^−/− CORT mice. F Quantitation of microglial VGlut2 engulfment in layer 5 mPFC of wildtype and C3^−/− mice. Data analyzed by two-way ANOVA, F(1,26) = 0.3373, p = 0.5664, n = 8 wildtype control, 8 wildtype CORT, 7 C3^−/− control, and 7 C3^−/− CORT mice. C–F All data shown as mean ± s.e.m. Source data provided in Source File.