Dietary n-3 polyunsaturated fatty acids revert renal responses induced by a combination of 2 protocols that increase the amounts of advanced glycation end product in rats

Abstract

Renal dysfunction is a severe complication that is caused by diabetes mellitus. Many factors associate the progression of this complication with high levels of proinflammatory and pro-oxidant substances, such as advanced glycation end products (AGEs), which form a heterogeneous group of compounds that can accumulate in tissues such as retinas, joints, and kidneys. The hypothesis of this study is that n-3 polyunsaturated fatty acids (n-3 PUFAs) have a nephroprotective effect on rats after exposing them to a combination of 2 protocols that increase the AGE amounts: a high-fat diet enriched with AGEs and a diabetes rat model. Adult Wistar rats were divided into 6 groups that received the following diets for 4 weeks: (1) control group; 2) HAGE: high AGE fat-containing diet group; (3) HAGE + n-3: high AGE fat-containing diet plus n-3 PUFAs group; (4) diabetic group; (5) Db + HAGE: high AGE fat-containing diet diabetic group; and (6) Db + HAGE + n-3: high AGE fat-containing diet plus n-3 PUFAs diabetic group. Diabetes mellitus was induced by an intraperitoneal injection of alloxan (150 mg kg(-1)). In diabetic and nondiabetic rats, the high HAGE fat-containing diet increased the serum creatinine, tumor necrosis factor-α, thiobarbituric acid reactive substances, and reactive oxygen species levels, as well as the superoxide dismutase/catalase + glutathione peroxidase ratio and the superoxide dismutase 2 and receptor for advanced glycation end products immunocontent of the kidneys. n-3 Polyunsaturated fatty acids attenuated these alterations and influenced the receptor for advanced glycation end products/oxidative stress/tumor necrosis factor-α axis. In summary, this study showed that the extrinsic AGE pathway (HAGE diet) had a greater effect on renal metabolism than the intrinsic AGE pathway (diabetes induction) and that n-3 PUFAs appear to prevent renal dysfunction via antioxidant and anti-inflammatory pathways.

Keywords: Dietary n-3 polyunsaturated fatty acids; High AGE fat–containing diet; Oxidative stress; Proinflammatory status; Renal parameters.