Background: Perivascular adipose tissue (PVAT) can regulate vascular homeostasis by secreting various adipokines. This study investigated the effects of PVAT browning on its endocrine function.
Methods: In the first section of our study, male Sprague-Dawley rats were randomly divided into cold exposure (8°C) and 24°C acclimation groups. After cold exposure for 7 days, interscapular brown adipose tissue (iBAT), subcutaneous white adipose tissue, thoracic aortic PVAT, and abdominal aortic PVAT (aPVAT) were harvested for histological and brown marker gene expression analysis. In the second part, male rats were fed a high fat diet (HFD) for 10 weeks. In the 11th week, the rats were treated with or without cold exposure. After 14-day cold exposure, aPVAT was collected for histological, gene, and protein expression analysis.
Results: Cold exposure had a browning effect on aPVAT by increasing UCP-1 and PGC-1α expression levels. After HFD feeding for 10 weeks, 14-day cold exposure was still able to induce aPVAT browning. Compared with thermoneutrality acclimation rats, TNF-α, IL-6, and p-p65 expression levels were significantly lower in aPVAT from HFD-fed rats with cold exposure. In contrast, p-AMPK expression levels were increased in aPVAT from HFD-fed rats with cold exposure.
Conclusions: Our study demonstrated that browning of aPVAT in HFD-fed rats lowered the pro-inflammatory adipokine expression levels and activated AMPK.
Keywords: AMPK; UCP-1; brown adipose; cold exposure; perivascular adipose.