Dietary effects of Raphanus sativus cv Sango on lipid accumulation and oxysterols in rat brain: a lipidomic study on a non-genetic obesity model

Introduction: Obesity is recognized as a leading global health concern, associated with an increased risk for several chronic diseases. The brain plays a key role in energy homeostasis as the master regulator of food intake balance and energy expenditure, controlling the adipose mass gain responding to hormonal and nutrient-related signals. Promising weigh-management strategies include the use of vegetables rich in bioactive compounds, to improve the antioxidant status and to stimulate lipid catabolism. The aim of this study was to evaluate the dietary effects of Raphanus sativus cv Sango on lipid accumulation and oxysterols in brain of obese rats. Materials and Methods: Four-day old Raphanus sativus cv Sango sprouts (SSJ) were squeezed to obtain a juice, which was collected and used for the experiments. Thirty-five male Sprague Dawley rats aged 9 weeks (270–300 g), after 10-days adaptation, were split randomly into five groups (7 animals per group) and fed specific diets: RD-RD (regular diet for 14 weeks); HFD-HFD (high fat diet for 14 weeks); HFD-RD (HFD for 10 weeks and then RD for 4 weeks); HFD-RD 75 (HFD for 10 weeks and then RD and 75 mg/kg b.w. SSJ for 4 weeks); HFD-HFD 75 (HFD for 10 weeks and then HFD and 75 mg/kg b.w. SSJ for 4 weeks). After 14 weeks, rats’ brains were isolated and their lipid matter was subjected to the analysis of total fatty acids, sterols and oxysterols composition. Results: The lipid content, fatty acid composition, cholesterol and its oxidation products (COPs) content were significantly affected. The HFD-HFD group showed a fat accumulation in the brain, with a significant reduction of linoleic acid. Although the lowest cholesterol content was detected on HFD-HFD group, the latter generated the highest COPs amount (63.098 microg/g brain). The main COPs foundwere 7alfa/beta-hydroxycholesterol, alfa/beta-epoxycholesterols, 7-ketocholesterol, cholestanetriol and 24-hydroxycholesterol. The Principal Component Analysis revealed that all COPs were highly correlated to HFD-HFD diet, except for 24-hydroxycholesterol which resulted highly correlated to linoleic acid content. Conclusions: The high fat diet increased lipid infiltration in rat brain, however, it reduced the amount of cholesterol with a significant increase of COPs, except for 24-hydroxycholesterol, thus confirming the inflammatory status. However, the Raphanus sativus cv Sango sprouts supplementation was not able to counteract the oxidative stress in rat brain since the lipidomic profile was not significantly affected