Fig. 4

T4 facilitates myelination in the developing rat brain. The developmental increase in brain MBP levels in thyroxine (T4)- and vehicle-treated rats aged 3–11 days old was determined by Resonance Raman Spectroscopy ELISA (RRS-ELISA) in homogenized brain lysates prepared from brain hemispheres. a The relationships between brain lysate MBP level and age in the two treatment groups are illustrated. T4 exhibited age-dependent positive effect on MBP levels. Data are presented as the mean ± SEM (n = 5–7). Statistical significance of differences between MBP levels in the two treatment groups at the analyzed age points is indicated as follows: **P < 0.01; ***P < 0.001 (Tukey’s multiple comparisons test following two-way ANOVA). b A significant positive correlation between brain lysate MBP levels and median FA distribution value in rat pups that underwent DTI. Red empty circles and black filled squares denote T4-treated and vehicle-treated pups, respectively