The effects of resveratrol on hepatic oxidative stress in metabolic syndrome model induced by high fructose diet.

BACKGROUND: The purpose of this study was to evaluate probable protective effects of resveratrol treatment on hepatic oxidative events in a rat model of metabolic syndrome (MetS). METHODS: Thirty-two male adult rats were randomly divided into 4 groups: control, fructose, resveratrol, and fructose plus resveratrol. To induce MetS, fructose solution (20 % in drinking water) was used. Resveratrol (10 mg/kg/day) was given by oral gavage. All treatments were given for 8 weeks. Serum lipid profile, glucose and insulin levels, liver total oxidant status (TOS) levels and paraoxonase (PON), glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT) activities were analyzed. RESULTS: Fructose-fed rats displayed statistically significant increases in TOS levels, and decreases in PON activity compared to the control group. Resveratrol treatment moderately prevented the decrease in liver PON activity caused by fructose. On the other hand, resveratrol, alone or in combination with fructose, did not change the TOS levels when compared to the fructose group. The SOD and CAT activities in all groups did not change. CONCLUSION: In this experimental design, high-fructose consumption led to elevated TOS levels and low PON activities. The resveratrol therapy shown beneficial effects on PON activity. However, it was found to behave like a prooxidant when administered together with fructose and alone in some parameters. Our results can inspire the development of new clinical therapy in patients with MetS (Tab. 2, Ref. 34).

The investigation of melatonin effect on liver antioxidant and oxidant levels in fructose-mediated metabolic syndrome model.

OBJECTIVE: Metabolic syndrome (MetS) can be induced by the oxidative stress conditions caused by ingestion of large amounts of fructose. We investigated the possible protective effects of melatonin administration on liver tissues in fructose-fed rats. MATERIALS AND METHODS: Thirty-two rats were randomly divided into four groups; control, fructose, melatonin, and fructose plus melatonin. MetS was induced by a fructose solution (20% in tap water) and melatonin (20 mg/kg daily) was administered by oral gavage. Systolic blood pressures (SBP) were measured. After the end of the 8-week experimental period, serum lipid profile, glucose and insulin levels, tissue total oxidant status (TOS) and activities of paraoxonase (PON), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) were measured. RESULTS: Fructose consumption significantly increased SBP, serum triglyceride and insulin levels and induced insulin resistance, confirming successful establishment of the MetS model. After fructose administration, the TOS levels and GSH-Px activities significantly increased in all groups compared to the control group. The PON activity in the fructose group significantly decreased compared to the control group. Melatonin supplementation, with or without fructose, increased PON activity. The SOD activity significantly increased in the fructose group compared to the control group, but significantly decreased in the melatonin group compared to the control and fructose groups. CAT activity was unchanged in all groups. CONCLUSIONS: GSH-PX and PON are important antioxidants for reducing oxidant stress. Melatonin might act as a prooxidant at the dose given in our experimental design when administered with fructose.

The study of biochemical and histopathological effects of spirulina in rats with TNBS-induced colitis.

OBJECTIVES: To evaluate the beneficial effects of spirulina on the treatment of experimental colitis. BACKGROUND: Spirulina, a planktonic blue green algae from oascillateriaceae family, has anti-inflammatory, antioxidant, antitumor, anti-viral, and antimicrobial effects, rendering it a natural drug of prophylactic and therapeutic properties. The effects of spirulina on colitis are not known. METHODS: Wistar rats weighing 200-300 g were used. Experimental colitis was created during anesthesia using the trinitrobenzene sulfonic (TNBS) acid. The rats were randomly divided into the 3 groups. In the group 1 (sham; n = 8), saline was administered via oral gavage 7 days after 1 ml of rectal saline was administered. In the group 2 (experimental colitis + spirulina; n = 8), 2 g/kg spirulina was administered via oral gavage 7 days after the rectal 1 ml TNBS was administered. In group 3 (experimental colitis; n = 8), enema was administered via oral gavage 7 days after the rectal 1 ml TNBS was administered. Eight days after the instigation of TNBS colitis, the rats were sacrificed and blood and tissue samples were taken. Histopathologic and immunohistochemical evaluations were conducted, and malondialdehyde (MDA), advanced oxidation protein products (AOPP), catalase (CAT), total antioxidant status (TAS), and glutathione (GSH) levels were determined. RESULTS: Inflammation on mucosa and submucosa, hemorrhage, necrosis, cellular infiltration and crypt abscess formation, immunoreactivity and tissue MDA levels were decreased in the experimental colitis + spirulina group when compared to the experimental colitis group (p < 0.05). CONCLUSION: The results of the present study indicate the beneficial effects of spirulina on TNBS-induced inflammatory bowel disease (Tab. 6, Fig. 10, Ref. 40).