Lycopene supplementation reduces TNF-α via RAGE in the kidney of obese rats

BACKGROUND: The kidney is a target organ for injuries caused by advanced glycation end products (AGEs) in obesity. The receptor of AGEs (RAGE) is proinflammatory and appears to have a role in the pathogenesis of renal disease due to obesity. OBJECTIVE: The aim was to verify the effect of obesity on renal damage and the effect of lycopene on these complications DESIGN AND METHODS: Male Wistar rats were randomly assigned to receive a control diet (C, n=7) or a high-fat diet plus sucrose (HD+S, n=14) for 6 weeks. After this period, the HD+S animals were randomized into two groups: HD+S (n=7) and HD+S supplemented with lycopene (HD+S+L, n=7). The animals received maize oil (C and HD+S) or lycopene (HD+S+L) for a 6-week period. RESULTS: The HD+S and HD+S+L animals demonstrated insulin resistance (OGTT glucose after 150 min; C: 117.6±3.9<HD+S: 138.1±5.1=HD+S+L: 137.8±5.2 mg dl(−1); P=0.01); however, no changes were seen in fasting glucose, plasma lipids, blood pressure or renal function. Renal concentrations of RAGE and TNF-α increased in the HD+S group and lycopene supplementation restored these to control group values (RAGE: C: 3.1±0.3=DH+S+L: 3.1±0.3<DH+S: 3.6±0.4 μg g(−1); P=0.014; TNF-α: C: 227.8±2.7=DH+S+L: 227.4±2.2<DH+S: 238.7±3.0 pg/ml; P=0.014). CONCLUSIONS: Lycopene may be beneficial in the prevention and treatment of oxidative stress and inflammation in the kidney due to obesity.