A Review of Brown Adipose Tissue Development in T2DM-SHR/N-cp (Corpulent) Rats

Abstract

Brown adipose tissue (BAT) plays a significant role in the expression of non-shivering thermogenesis in response to perturbations in diet and environment in man and animals. The SHR/N-cp rat is an animal model of obesity and T2DM and has been reported to exhibit an impaired thermogenic response to parameters of diet and environment. Groups of lean and obese male SHR/N-cp rats were maintained in hanging wire-bottomed steel cages and fed a nutritionally complete diet containing 54% CHO, 22% protein,16.5% mixed fats, and 4.5% essential fiber, plus vitamins, minerals, and essential micronutrients from 1 to 9 months of age. Measures of body weight were monitored and 24-hour urinary vanil mandelic acid (VMA) were determined at the end of the study. Animals were sacrificed by decapitation and the Interscapular BAT depots excised in their entirety for measures of adipocyte size, number, and lipid content. Bode weights, net weight gain and relative adiposity of Obese was significantly greater than their lean littermates throughout the study. Urinary VMA of lean > obese rats. The IBAT weight and IBAT weight: Body weight of obese >> lean. IBAT cell number, cell lipid content and % lipid of IBAT tissues of obese >> lean rats. The results of this study indicate that while the development of IBAT mass and cellularity becomes exaggerated in the obese-diabetic animals, the superimposition of the T2DM stigmata including likely insulin resistance may further compromise the capacity of the obese diabetic animals to fully express BAT-mediated contributions to nonshivering thermogenesis .