Assessment of the Aging of the Brown Adipose Tissue by F-FDG PET/CT Imaging in the Progeria Mouse Model Lmna.

Brown adipose tissue (BAT) is an important energy metabolic organ that is highly implicated in obesity, type 2 diabetes, and atherosclerosis. Aging is one of the most important determinants of BAT activity. In this study, we used F-FDG PET/CT imaging to assess BAT aging in Lmna mice. The maximum standardized uptake value (SUV) of the BAT was measured, and the target/nontarget (T/NT) values of BAT were calculated. The transcription and the protein expression levels of the uncoupling protein 1 (UCP1), beta3-adrenergic receptor (3-AR), and the PR domain-containing 16 (PRDM16) were measured by quantitative real-time polymerase chain reaction (RT-PCR) and Western blotting or immunohistochemical analysis. Apoptosis and cell senescence rates in the BAT of WT and Lmna mice were determined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and by CDKN2A/p16INK4a immunohistochemical staining, respectively. At 14 weeks of age, the BAT SUV and the expression levels of UCP1, 3-AR, and PRDM16 in Lmna mice were significantly reduced relative to WT mice. At the same time, the number of p16INK4a and TUNEL positively stained cells (%) increased in Lmna mice. Collectively, our results indicate that the aging characteristics and the aging regulatory mechanism in the BAT of Lmna mice can mimic the normal BAT aging process.