Figure 3
LPS altered postsynaptic cluster density and area, and mossy fiber terminal area in the CA3 region. PSD95:GFP-expressing retroviruses were delivered into the hippocampus, and LPS was administered during different periods, following the experimental design shown in Supplementary Figure S1. Mice were killed 4 and 8 weeks after retroviral injections to analyze newborn neuron connectivity. (a–f) Representative pictures showing retrovirus-labeled neurons of different ages belonging to the diverse experimental conditions. (g, i) Quantification of the postsynaptic cluster density of (g) 4- and (i) 8-week-old neurons. LPS slightly reduced the postsynaptic cluster density of 4- and 8-week-old neurons. (h, j) Quantification of the postsynaptic cluster area of (h) 4- and (j) 8-week-old neurons. No relevant changes in postsynaptic cluster area were observed in 4-week-old neurons (h); however, a significant and permanent decrease of distal postsynaptic cluster area was observed in 8-week-old neurons (j). This effect was not reversed by ibuprofen treatment. (k–n) Representative images showing mossy fiber terminals (MFTs) of retrovirus-labeled neurons of different ages belonging to the diverse experimental groups. (o) Quantification of mossy fiber terminal area in the CA3 region. LPS administration produced only minor changes in the mossy fiber terminal area of 4-week-old neurons but significantly and permanently decreased the presynaptic terminal area in 8-week-old ones, regardless of the cell age at which it was applied and the recovery period. ibuprofen did not counteract the aforementioned effect. Yellow scale bar, 50 μm. Blue scale bar, 10 μm. Yellow triangles, mossy fiber terminal. (*, 0.01<P<0.05) (**, 0.001<P<0.01) (***P<0.001) (!, 0.05<P<0.1). GL, granule layer; h, hilus; LPS, lipopolysaccharide; ML, molecular layer; PBS, phosphate-buffered saline.
