Effects of burn injury, cold stress and cutaneous wound injury on the morphology and energy metabolism of murine brown adipose tissue (BAT) in vivo.

Abstract Aims Cold stress has been shown to produce dramatic increases in 2-fluoro-2-deoxy-D-Glucose ( 18 FDG) accumulation by brown adipose tissue (BAT) in rodents. However, neither the effects of other types of stress on 18 FDG accumulation nor the effects of stressors on the accumulation of tracers of other aspects of energy metabolism have been evaluated. In this report we studied the effects of cold stress, burn injury and cutaneous wounds on murine BAT at the macroscopic, microscopic and metabolic level. Main methods Glucose metabolism was studied with 18 FDG, fatty acid accumulation was evaluated with trans-9(RS)- 18 F-fluoro-3,4(RS,RS)-methyleneheptadecanoic acid (FCPHA) and tricarboxcylic acid cycle (TCA) activity was evaluated with 3 H acetate. Key findings All three stressors produced dramatic changes in BAT at the macroscopic and microscopic level. Macroscopically, BAT from the stressed animals appeared to be a much darker brown in color. Microscopically BAT of stressed animals demonstrated significantly fewer lipid droplets and an overall decrease in lipid content. Accumulation of 18 FDG by BAT was significantly ( p 18 FDG, BAT uptake of FCPHA and acetate were also significantly increased by all three treatments. These findings suggest that in addition to cold stress, burn injury and cutaneous wounds produce BAT activation in mice. Significance This study demonstrates brown fat activated by several stressors leads to increased uptake of various substrates.