Blueberry juice attenuates liver injury progression in a rat model of diet-induced prediabetes

Blueberries bioactive compounds have recognized benefits on metabolic disorders1,2; however, the effects of blueberry juice (BJ) against progression from prediabetes to diabetes are completely unknown. This study aimed to evaluate the impact of BJ on the evolution of metabolic dysregulation, with a major focus on hepatic tissue, using a prediabetic animal model. Prediabetic male Wistar rats (8 weeks old) were developed by ingestion of an high-sucrose diet (HSu, 35%) for 9 weeks (W9).3 In order to aggravate the prediabetic state, animals were submitted to a high-fat diet (HF, 60% calories from fat) for further 14 weeks (HSuHF) (W23). BJ were given orally at 9 weeks after HSu diet consumption, as a preventive strategy (between W9 to W23) (according to Figure 1). At each time-point, glycemic, insulinemic and lipidic profiles were assessed; markers of redox status were analysed on serum and liver tissue. Hepatic characterization in terms of morphology, echogenicity, fibrosis/steatosis and mitochondrial function were evaluated by ultrasonography, histochemical staining techniques and bioenergetics assays, respectively. HsuHF rats displayed metabolic dysregulation as well as hepatic focal steatosis and liver mitochondrial bioenergetics deficits. Notably, BJ treatment (HsuHF/BJ group) improved glucose tolerance, insulin sensitivity and hypertriglyceridemia along with an amelioration on hepatic histomorphological and functional features as seen by improved steatosis and mitochondrial function. Overall, this work provides novel evidence on BJ ability to prevent the aggravation of prediabetes induced by Hsu/HF diet with notable benefits on hepatic tissue, although the precise mechanisms should be further explored.