Effect of tart cherry supplementation on brown adipose tissue of high fat diet obese rats.

This study is a part of a project aimed to assess the effects of tart cherries on a commonly used rat model of diet-induced obesity (DIO). To date, a preventive effect of tart cherry against the onset of obesity-related risk factors and its protective role against oxidative stress and liver steatosis has been demonstrated [1]. In addition, a decrease of inflammation in the visceral fat has proven to be associated with tart cherry supplementation [2].Here, we have investigated the impact of a high-fat diet (HFD) on interscapular brown adi-pose tissue (iBAT) in DIO rats and the possible beneficial effects of tart cherries in addition to the high caloric diet. Rats were divided into 3 groups fed an HFD (DIO), an HFD added with seed powder (DS), and an HFD added with seed powder plus juice (DJS) of Prunus cerasus L. The ani-mals were monitored for 17 weeks and compared to control fed with standard diet (CHOW). Histologic observations revealed that HFD induces iBAT dysfunction in DIO rats, character-ized by expansion of white adipose tissue versus iBAT, mainly through the conversion of brown adipocytes to white-like unilocular cells. Although with individual differences, tart cherry sup-plementation resulted in a reduction of obesity-induced whitening of iBAT both in DS and in DJS, compared to DIO rats. No differences in tissue weight were found among the obese groups.A lower intensity of the Uncoupling Protein 1 (UCP1) staining in brown adipocytes and a higher amount of weakly or negative white-like brown adipocytes in both supplemented groups were found. These results were also confirmed by the WB results. As expected, based on the large brown to white conversion in obesity, the gene expression analysis showed a decreased UCP1 gene and related peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PCG-1a) expression in DIO rats respect to the controls. Instead, in the obese DS rats, the upregulation of the thermogenic genes not only concerning DIO rats but also control might suggest the activation of a tissue remodeling program, distinct from that induced in DIO rats.Finally, additional immunochemical investigations indicated that tart cherry supplementation would attenuate the obesity-induced profile of both inflammatory markers and Glucose-Regulated Protein 94 (GRP94) protein, suggesting the possible effectiveness of both juice and seeds against the pro-inflammatory environment and the ability to improve the recovery of the ER function.