Fig. 1

LPS challenge increases BLB permeability and causes hearing loss. (A) Experimental design scheme. LPS was injected IP at 5 and 10 mg/kg on two consecutive days. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI; 45 cycles, IV injection of contrast agent at cycle 7), Evans blue (EB) level quantification and auditory brainstem responses (ABR) recording were performed at different time points after LPS challenge. (B) Representative T1-weighted horizontal head images obtained at the end of DCE-MRI in rats from control and LPS groups, 72 h after challenge. Detail of the cochlea is shown in the white square. C-D) Time-course of the signal enhancement (mean ± SE) along the DCE-MRI (C) or in a representative 30th cycle (D) in control rats without LPS (white; n = 16 for time 0 h) and in LPS-injected rats (red; n = 4 rats for 0.5, 1, 2 and 4 h; n = 8–9 for 25 and 48 h and n = 16 for 72 h). E) EB concentration (mean ± SE, in ug/mg) in the inner ear from control (white, n = 6) and LPS-injected rats (red, n = 3–6), 1–2, 25 and 72 h after LPS challenge. F) ABR thresholds (mean ± SE, in dB SPL) before (white circles) and 72 h after (red circles) LPS injection in rats from the LPS group (n = 31). Statistically significant differences were calculated using Kruskal-Wallis (D, E) or Mann-Whitney (F) tests (*p < 0.05, **p < 0.01, ***p < 0.001)