Effect of broccoli extract enriched diet on liver cholesterol oxidation in rats subjected to exhaustive exercise

Introduction: Sulforaphane (SF), an isothiocyanate from cruciferous vegetables, has proven to counteract oxidative stress induced apoptosis and to act as an indirect antioxidant in many organs and tissues. Since acute exhaustive exercise promotes ROS generation, the aim of this study was to evaluate the effect of a broccoli extract enriched diet on cholesterol oxidation in liver of rats subjected to exhaustive exercise. Materials and Methods: Thirty two male Wistar rats (age: 4 months, average weight: 230 g) were randomly divided into four groups: control diet without exercise (CC), enriched diet (average daily consumption: 0.15 mg of SF per rat) without exercise (CSF), control diet with acute exhaustive exercise (CW) and enriched diet with acute exhaustive exercise (WS). The study lasted 45 days and on the ultimate day, rats of groups CW and WS were forced to run until exhaustion on a treadmill. Immediately after the exercise protocol, all rats were slaughtered, and their livers were isolated and grouped into four pools of 2 livers each per single treatment. Livers were subjected to direct cold saponification, SPE-NH2 purification and the cholesterol oxidation products (COPs) fraction was injected into FAST GC/MS. Results: The main COPs found were 7α-hydroxycholesterol, 7β-hydroxycholesterol, 7-ketocholesterol, cholestanetriol, 24-hydroxycholesterol and 27-hydroxycholesterol. In general, the SF-enriched diet led to reduced cholesterol oxidation. The highest level of COPs (0.985±0.155 microg/g liver) was found in the CW group, whereas the WS rats showed the lowest value (0.237±0.080 microg/g liver). Moreover, the CSF group had a higher content of COPs (0.397±0.021 microg/g liver) than CC (0.503±0.064 microg/g liver). Conclusions: This study suggests that SF had an antioxidant effect towards cholesterol oxidation in liver of rats, particularly evident under exhaustive exercise conditions, and thus could play a critical role in the modulation of the redox environment and on the prevention of oxidative damage.