Assessment of the Aging of the Brown Adipose Tissue by (1) (8)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 (18)F-FDG PET/CT imaging to assess BAT aging in Lmna(−/−) mice. The maximum standardized uptake value (SUV(Max)) 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 (β3-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(Max) and the expression levels of UCP1, β3-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.