Fig. 1

Disruption of hypothalamic myelin structure induced by chronic HFD feeding. a Brain tissue sections collected from mice receiving Chow and HFD feeding for 4 months, and then subjected to immunofluorescence for MBP (red) and Olig-2 (green). DAPI nuclear counterstaining (blue) was also conducted. b Total proteins were prepared from the hypothalamic tissues collected from animals receiving Chow or HFD for 4 months, and then subjected to western blot analysis for the measurement of MBP, PLP, and β-actin (loading control). The quantification of hypothalamic MBP and PLP level normalized by relative β-actin level was performed. The results are presented as mean ± SEM (n = 5 animals for each time point). *p < 0.05 versus the Chow group. c The hypothalamic tissue was removed from Chow and HFD-fed animals at 4 month after feeding (n = 3 animals for each group), and then subjected to TEM imaging analysis. TEM images from the HFD group show the disrupted myelin surrounding the axons (arrows) and swollen/fragmented mitochondria (starlet). d The diagram illustrates that mice were fed by Chow and HFD for 6 months, as well as HFD for 3 months and Chow for another 3 months (HFD withdrawal). e The hypothalamic tissue sections were prepared from two Chow-fed mice, two HFD-fed mice, and two HFD withdrawal mice for TEM imaging analysis. The representative images indicate that the disorganized myelin was found in the hypothalamic tissue from the HFD-fed group (arrows), and mitochondrial fragmentation was observed (starlet). Yet, hypothalamic myelin structure in the HFD withdrawal group displayed more compact than that observed in the HFD group. Scale bar in a 200 μm; in c, e 500 nm