Consumption of out-of-season orange modulates fat accumulation, morphology and gene expression in the adipose tissue of Fischer 344 rats

Abstract

Purpose According to the xenohormesis theory, animals receive signals from plants that give clues about the changing environment, and thus, depending on the season of the year, animals develop physiological changes to adapt in advance to the seasonal changes. Our objective was to study how the same fruit cultivated during two different seasons could affect the adipose tissue of rats. Methods Thirty-six Fischer 344 rats were acclimated for 4 weeks to long-day or short-day (SD) photoperiods. After adaptation, three groups (n = 6) from each photoperiod were supplemented either with orange from the northern (ON) or southern (OS) hemispheres harvested in the same month or a vehicle (VH) for 10 weeks. Biometric measurements, postprandial plasmatic parameters, gene expression of the inguinal white adipose tissue (IWAT) and brown adipose tissue (BAT), and the histology of the IWAT were analysed. Results The OSSD group increased its fat content compared to the VHSD, while the ON groups showed no biometric differences. The OS groups were further studied, and the IWAT showed increased levels of Pparγ gene expression and a higher percentage of larger adipocytes compared to the VH group. The BAT showed down-regulation of Lpl, Cpt1b and Pparα in the OSSD group compared to that in the VHSD group, suggesting an inhibition of BAT activity, however, Ucp1 gene expression was up-regulated. Conclusions We observed a different effect from both fruits, with the OS promoting a phenotype prone to fat accumulation when consumed in an SD photoperiod, which might be explained by the xenohormesis theory.

A Mix of Natural Bioactive Compounds Reduces Fat Accumulation and Modulates Gene Expression in the Adipose Tissue of Obese Rats Fed a Cafeteria Diet

“…For histological analyses, frozen IWAT samples were thawed and fixed in 4% formaldehyde and processed as explained previously [ 38 ].…”

“…The area and number of adipocytes were measured using the open source software Adiposoft (CIMA, University of Navarra, Spain). Four fields per sample and six samples from each group were measured, and the area, total adipocyte number, and adipocyte size frequencies were calculated as explained previously [ 38 ].…”

“…The protein content was quantified using a BCA protein assay kit (Pierce, Rockford, IL, USA), and the anti-Fasn antibody was acquired from Abcam (Cambridge, United Kingdom). The Western blot and protein level quantification were performed as described previously [ 38 ].…”

Chrononutrition and Polyphenols: Roles and Diseases

“…Similarly, the out-of-season consumption of navelina oranges ( Citrus x sinsensis ) for ten weeks in the same animal model also exerted deleterious effects induced by an obesogenic diet, such as dyslipidemia and insulin resistance, increasing fatty acid synthesis in white adipose tissue and downregulating lipid uptake and β-oxidation in brown adipose tissue [119].…”

“…Therefore, the physiological and molecular changes elicited by seasonal fruit consumption could be partially explained by the modulation of the mammalian clock system. In fact, the consumption of both Prunus avium L. and Citrus x sinsensis has been correlated with the modulation of mRNA levels of different peripheral clock-related genes such as Nr1d1 in skeletal muscle and Per2 and Cry1 in the liver and white adipose tissue of healthy rats when they are consumed out of season [116,117,119]. In accordance, previous studies performed by our group have demonstrated that grape seed proanthocyanidins (PAs), a subclass of flavonoids with a marked protective effect against diet-induced dyslipidemia and insulin resistance [94], could significantly modulate both central and peripheral biological rhythms in male Wistar rats.…”