Effect of high fat diet on intake, energy, insulin resistance, glucose tolerance and brown adipose tissue microscopy in C57BL/6 mice.

摘要

Brown Adipose Tissue (BAT) generates heat, being rich in mitochondria and vessels, but normally with low fat levels. However, in obesity, fat accumulates in BAT cells which can then induce fibrosis. We report effect of high fat (HF) diet on intake, energy, insulin resistance, glucose tolerance and BAT histology in C57BL/6 mice. Groups of 10 mice each were fed HF diet of 21kJ/g energy and control standard diet with 15kJ/g for 14 days. In those given HF we found increased mean body mass (~22%), feed intake (28%), plasma glucose (30%), intraperitoneal (42%) and oral insulin resistance (~38%) but a decline in insulin sensitivity (~-44%). BAT volume was ~54% in mice given HF diet and ~81% in controls whereas white fat content was much higher in those given HF (33%) compared with controls (5.7%). Vascularization in mice given HF was ~4.5% compared with controls (7.4%). We found increased fibroblast (8.4%) response in mice given high fat diet compared with controls (6.1%) suggesting inflammation. Significance for mean differences ranged P < 0.005-0.0001. The findings suggest that high fat diets may induce inflammation and whitening in brown adipose tissue, with insulin resistance and glucose intolerance, but without fibrosis in mice.