In situ fluorescence-photoacoustic measurement of the changes of brown adipose tissue in mice under hindlimb unloading

作者：Gong, Baojie; Tang, Jianxin; Jiang, Xiaoxiao; Zhang, Zhe; Li, Shiying; Jin, Hongjun; Nie, Liming^*; Huang, Guojia^*

来源：Journal of Applied Physiology, 2023, 135(2): 251-259.

DOI：10.1152/japplphysiol.00212.2023

• brown adipose tissue
• fluorescence imaging
• hindlimb unloading
• photoacoustic imaging

Space travel causes rapid weight loss of astronauts, but the underlying reasons are still obscure. Brown adipose tissue (BAT) is a well-known thermogenesis tissue that is innervated by sympathetic nerves, and norepinephrine stimulation can promote the thermogenesis and angiogenesis of BAT. Herein, the structural and physiological changes of BAT as well as serological indicators were investigated in mice under hindlimb unloading (HU) to simulate a weightless environment in space. The results showed that long-term HU could induced the thermogenic activation of BAT by upregulating the mitochondrial uncoupling protein. Further, peptide-conjugated indocyanine green was developed to target the vascular endothelial cells of BAT. Noninvasive fluo-rescence-photoacoustic imaging presented the neovascularization of BAT on the micron scale in the HU group, accompanying by the increase of vessel density. Downward trend of serum triglyceride and glucose level of mice treated with HU proved the more heat production and energy consumption in BAT compared with the control group. This study suggested that HU may be an effective strategy to curb the occurrence of obesity, whereas fluorescence-photoacoustic dual-modal imaging showed capa-bility of assessing BAT activity.

• 单位
  中国医科大学; 南方医科大学; 广东省人民医院; 5; 中山大学