Fig. 2.

Differential effect of sterile and microbial intra-amniotic inflammation on an MRI imaging biomarker of free radical production/oxidative stress in the foetal brain. (a) Left: Dams were intra-amniotically injected with IL-1α (25 ng/25 μL per sac) or LPS (100 ng/25 μL per sac). Six h later, a portion of dams from each group received an intraperitoneal injection of rosiglitazone (ROSI; 10 mg/kg), and all dams underwent in utero MRI scanning using a 7T system. Continuous production of paramagnetic free radicals (indicative of oxidative stress) in the region of interest (ROI) located in the left and right brain hemispheres was inferred from the difference in the R1 (=1/T1) signal between ROSI-treated (a drug with antioxidant properties) and untreated dams. Right: Representative image showing the foetal brain. (b) Top row: Representative anatomical images (generated by normalizing the TR 150 ms image) for each study group. Bottom row: Corresponding R1 maps. All images were fixed to the same scale with darker colours indicating lower R1 values. (c) Modelled mean of the ROI R1 from both hemispheres of either IL-1α and IL-1α + ROSI groups (left bar graph, n = 6 per group) or LPS and LPS + ROSI groups (right bar graph, n = 3–4 per group). Data are presented as means and confidence intervals. p-values were determined using linear mixed modelling. ∗p < 0.05.