A high fructose diet induces protein glycoxidation and HNE protein modifications in rats

Protein oxidative modifications are involved in the onset and progression of cell and tissue damage induced by a high fructose diet (HFD) (1) (2). The aim of the present work is to investigate the glycoxidative protein pattern as well as the formation of lipid derived reactive carbonyl species (RCS) protein adducts in rats fed HFD. Sprague Dawley rats (n=20) were divided into two groups: one group was fed with 60% HFD and the other received a standard diet (control). After 42 days of HFD, blood, urine and tissue samples were collected. CML and CEL protein modifications in plasma and urine were determined by ELISA while HNE protein adducts formation in plasma was determined by a validated western-blot analysis, using HSA-HNE adducts as external standard, prepared as previously described (3) and fully characterized by ESI-MS analysis. HFD ratscompared to control rats showed metabolic syndrome conditions, characterized by hypertension, dyslipidemia (increase of plasma TG and cholesterol), insulin resistance, kidney damage (increase of urinary albumin and protein and plasma creatinine), inflammatory response and a sustained systemic oxidative stress as measured by urinary isoprostanes. CEL and CML increased in urine of HFD rats by 2.5 and 2 fold (p<0.001) in respect to control rats. HNE protein adducts content in plasma was determined by a validated western-blot approach showing a dynamic range of 46pmoL-1.4pmoL, and a calibration curve with a correlation coefficient greater than 0.99885. HNEalbumin content significantly increased almost 12 fold in the plasma of HFD in respect to controls (p<0.05). In conclusion, HFD induces AGEs formation, which most likely through RAGE activation, gives an inflammatory response and oxidative damage, which in turn promotes HNE formation which further sustains the damage induced by HFD.