The effect of resveratrol on glycation and oxidation products in plasma and liver of chronic methylglyoxal-treated rats.

BACKGROUND: Methylglyoxal (MG) is a highly reactive dicarbonyl compound. It is produced by processes like glycolysis, glucose autooxidation, lipid peroxidation, and protein glycation. It is a major precursor of advanced glycation end products (AGE). It also exacerbates oxidative stress in the organism. Although there are some in vitro studies investigating the effect of resveratrol (RES) as an antioxidant and antiglycating agent on MG-induced toxicity, in vivo effect of RES is unknown. Therefore, we aimed to investigate the efficiency of RES in chronic MG-treated rats. METHODS: Rats were given incrementally increased doses (100-300 mg/kg) of MG in drinking water for ten weeks. RES (10 mg/kg ip) was administered together with MG. Reactive oxygen species (ROS) formation, thiobarbituric reactive substances (TBARS), protein carbonyl (PC), advanced oxidation protein products (AOPP) and AGE levels as well as ferric reducing antioxidant power (FRAP) values were determined in plasma and liver. RESULTS: Significant increases in plasma TBARS, PC, AOPP and AGE and fructosamine levels were detected in MG-treated rats. However, plasma ROS and FRAP levels remained unchanged. Hepatic ROS, TBARS, PC and AOPP, but not AGE and FRAP levels were also increased in MG-treated rats. RES treatment diminished high levels of plasma PC, AOPP and AGE levels in MG-treated rats. Additionally, significant decreases in hepatic ROS, TBARS, PC and AOPP levels together with histopatological amelioration were detected due to RES treatment in MG-treated rats. CONCLUSIONS: Our results indicate that RES may be considered as a protective agent against glycoxidative stress generated by in vivo MG treatment.

Antiglycation and anti-oxidant efficiency of carnosine in the plasma and liver of aged rats.

AIM: Increases in oxidative stress and advanced glycation end-products (AGE) formation play an important role in the pathogenesis of aging. Carnosine (CAR; ß-alanyl-L-histidine) has anti-oxidant and antiglycating properties. We investigated the effect of CAR supplementation on AGE levels, and protein and lipid oxidation products in the serum and liver tissue in aged rats. METHODS: Young (3 months-of-age) and aged (20 months-of-age) rats were injected with CAR (250 mg/kg/daily; i.p.; 5 days per week) for 2 months. At the end of this period, AGE, protein carbonyl, advanced oxidized protein products, and malondialdehyde levels were determined in the serum and liver tissue. Furthermore, reactive oxygen species formation and ferric reducing anti-oxidant power values were measured. RESULTS: AGE, malondialdehyde, protein carbonyl and advanced oxidized protein products levels, and reactive oxygen species formation were higher in the serum and liver tissue of aged rats compared with young rats. CAR treatment was observed to significantly decrease AGE, malondialdehyde, protein carbonyl and advanced oxidized protein products levels, and reactive oxygen species formation in the serum and liver of aged rats. CONCLUSIONS: These results clearly show that CAR might be useful for decreasing glycoxidant stress in aged rats. Geriatr Gerontol Int 2017; 17: 2610-2614.

The effect of carnosine on methylglyoxal-induced oxidative stress in rats.

Methylglyoxal (MG) is generated from glycolytic metabolites, lipid peroxidation, glucose autooxidation and protein glycation. It is a prooxidant inducing oxidative stress and formation of advanced glycation end products (AGE). Effect of carnosine (CAR) as an antioxidant on toxicity due to MG has generated interest. In this study, rats were given incrementally increased doses (100-300 mg/kg) of MG in drinking water for ten weeks. CAR (250 mg/kg i.p.) was administered with MG. Plasma thiobarbituric reactive substances (TBARS), protein carbonyl (PC), advanced oxidation protein products (AOPP) and AGE levels were elevated by MG, and CAR decreased PC, AOPP and AGE levels. MG increased liver reactive oxygen species (ROS), TBARS, PC and AOPP levels, which were decreased by CAR. Thus, in vivo role of CAR on chronic MG administration was observed to suppress the generated hepatic and plasma oxidative stress.