Effects of Berries on High-Fat Diet-Induced Inflammation
Abstract Objectives Studies suggest that inflammation mediates the link between obesity and its comorbidities including type 2 diabetes and cardiovascular disease. Hence, there is a demand for effective alternative or complementary approaches to treat obesity-associated inflammation. The objective of this study was to determine whether consumption of blackberries (BL) and raspberries (RB) alone or in combination reduce obesity-induced inflammation. Methods In Vitro Study: RAW 264.7 macrophages were pretreated with either BL, RB, or BL + RB, each at a final concentration of 200 µg/mL for 2 h. LPS (1 ng/mL) was then added to the media for 16 h. mRNA expression of inflammatory cytokines was measured. In Vivo Study: Five-week-old mice were acclimated to a low-fat low-sucrose (LFLS) diet for one week after which mice were randomized 10 per group to one of five groups: 1) LFLS, 2) high-fat high-sucrose (HFHS), 3) HFHS + 10% BL, 4) HFHS + 10% RB, or 5) HFHS + 5% BL + 5% RB. Expression of inflammatory markers was measured in the liver as well as epididymal and inguinal white adipose tissue. Results In Vitro Study: Each berry alone and in combination suppressed the LPS-induced increase in inflammatory markers, with the combination (BL + RB) having the greatest effect. The combination suppressed LPS-induced expression of Ccl2, Tnfa, F4/80, and Il6 by 3.7−, 5.3−, 5.3−, and 4.4-fold, respectively. In Vivo Study: Gene expression analysis indicated that berry consumption had no significant effect on proinflammatory (Ccl2, Il1b, Tnfa, Il6, Itgam) or anti-inflammatory (Adipoq, Arg1, Mgl1) markers in adipose tissue depots or liver. However, relatively low gene expression of inflammatory markers in the tissues indicates that the mice fed the HFHS diet failed to develop a robust inflammatory state. Conclusions BL and RB have direct anti-inflammatory effects on immune cells. Initial analysis indicates that consumption of BL and RB has no significant effects on markers of inflammation in a diet-induced mouse model of obesity. However, it is possible that the relatively low levels of inflammation in these mice masked the anti-inflammatory potential of BL and RB. Ongoing analysis will provide additional insights into the effects of BL and RB on inflammation in these tissues. Funding Sources Lewis Foundation Award.
