Fig. 2

LPS challenge does not cause hair cell loss or synapse alterations. (A) Paraffin midmodiolar cochlear sections stained with hematoxylin-eosin. General view of the cochlear middle turn (a) and detail of the organ of Corti (b, d) and spiral ganglion (c, e) of rats from control and LPS experimental groups, 72 h after first injection, showing no evident alterations. Scale bar: 50 μm (a) and 10 μm (b). (B) Inner (IHC) and outer (OHC) hair cell counts (mean ± SE) in the organ of Corti from apical (4–8 kHz), middle (16–24 kHz) and basal (32–40 kHz) turns, in control (n = 3, white) and LPS (n = 4, red) rats, 72 h after challenge. (C) Representative confocal images of organ of Corti whole mounts at apical (4 kHz), middle (16 kHz) and basal (32–40 kHz) cochlear turns from control and LPS-injected rats, immunolabeled for MyoVIIa (blue), CtBP2 (green), and GluR2/3 (red) for synapse evaluation. Red and green arrowheads indicate individual post- and presynaptic marker staining, respectively, and white arrowheads indicate co-localized CtBP2-GluR2/3 puncta. Scale bar: 8 μm. (D) Quantification of orphan CtBP2, orphan GluR2/3 and co-localized CtBP2-GluR2/3 puncta per IHC in control (n = 3) and LPS-injected (n = 4) rats. Data presented as mean ± SE.