Fig. 6.

Betaine supplementation prevented the ER stress response in adipose tissue induced by high-fat feeding. Male C57BL/6 mice were fed with a high-fat diet with/without betaine supplementation (1%) in the drinking water for 12 wk. Total protein extracts from epididymal fat pads were prepared thereafter. Protein (40 μg) was subjected to Western blot analysis for glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), and c-Jun NH₂-terminal kinase (JNK) phosphorylation using specific antibodies. A: prolonged high-fat feeding caused a significant increase of both GRP78 and CHOP levels in adipose tissue, which was prevented by betaine supplementation. B and C: quantitation of Western blots of GRP78 and CHOP expression levels in adipose tissues from different groups, normalized by corresponding glyceraldehydes-3-phosphate dehydrogenase (GAPDH) expression levels (n = 8). D: betaine supplementation prevented JNK activation by high-fat feeding. E: quantitation of Western blots of JNK phosphorylation levels in adipose tissues from different groups, normalized by corresponding GAPDH expression levels (n = 8). Data are indicated as means ± SD. Bars with different letters differ significantly (P < 0.05).