Modulation of Age-Related Biochemical Changes and Oxidative Stress by Vitamin C and Glutathione Supplementation in Old Rats

Abstract

The present study sought to determine whether supplementation of dietary antioxidant ascorbic acid with glutathione (GSH) could ameliorate the age-related increased oxidative stress and changes in hormonal, lipid and copper (Cu) as well as zinc (Zn) levels in 18-month-old rats. The present study demonstrated that supplementation of vitamin C (30 mg) + GSH 100 mg/kg b.w. significantly reduced the concentration of thiobarbituric acid-reactive substances in liver and testes in old male rats as compared with nonsupplemented ones, indicating lower oxidative stress. In addition, testicular GSH was increased but not hepatic GSH. Also, cholesterol and triglycerides were decreased in the serum of supplemented rats. Furthermore, she serum testosterone level was increased in the same supplemented rats. However, the present results show that the thyroid hormones, T₃ and T₄, were not influenced. Lastly, the concentration of Cu in serum, liver, brain and testes was increased in supplemented old rats. Zn concentration was also increased in the same organs but not in the liver. According to the present study, the supplementation of antioxidants could play an important role in the modulation of the oxidative damage and changes associated with age.

Melatonin prevents oxidant damage in various tissues of rats with hyperthyroidism

“…The rats we used in our study were 3 months old, whereas those in the other study were 1.5 years old. Previous studies have suggested that oxidant and antioxidant system activities changed with age (Amer, 2002;Shinohara et al, 2000). Oxidative damage caused by hyperthyroidism in cerebral tissue was prevented to a great extent by melatonin administration and an increase was observed in levels of GSH, which is an indicator of antioxidant system activity.…”

Lipid peroxidation in kidney and testis tissues in experimental hypothyroidism: the role of zinc

“…Similarly, Tang et al (21) reported in their study that zinc prevented pathological renal changes in diabetic rats. In the same vein, Amer et al (22) demonstrated the antioxidant characteristics of zinc in old rats. It was also reported in previous studies that zinc metallothionein offered a signifi cant degree of protection in the kidney (10) and testis (9).…”

Evaluation of the hepatic reduction of a nitroxide radical in rats receiving ascorbic acid, glutathione or ascorbic acid oxidase by in vivo electron spin resonance study

“…Doses of 250 mg/kg AsA, 25 mg/kg GSH and 500 U/kg AAOx might be too high 20,22 . In preliminary experiments, we observed ESR signals of TEMPOL in the liver of rats, which orally received AsA at doses of 150 and 250 mg/kg.…”

“…Conversely, there was no difference in TEMPOL half‐life in the liver homogenate between the GSH treated‐rats and controls. It is thought that the additional GSH‐related increase in the amount of AsA in the plasma is because the GSH intracellular concentration in the liver is higher than the plasma GSH concentration 20,23 . Furthermore, reaction kinetic analysis shows that TEMPOL half‐lives observed in the liver using SCR reflect the hepatic reducing ability of TEMPOL.…”