Changes of oxidative stress in various tissues by long-term administration of vitamin E in hypercholesterolemic rats

Background: Free radical-mediated oxidative stress has been implicated in the genesis and progression of atherosclerosis. Methods: The lipid peroxides and antioxidant status of various tissues were investigated in hypercholesterolemic rats and the effect of vitamin E supplementation on defense systems. Results: Cholesterol-feeding caused a significant increase in the lipid peroxide concentrations of plasma, erythrocytes, liver and brain. In addition, a significant decrease in glutathione (GSH) content, glutathione peroxidase (GSH-Px) and glutathione transferase (GSH-ST) activities were found in erythrocytes and liver but superoxide dismutase (SOD) activity remained unchanged in these tissues in comparison to the control group. Vitamin E supplementation to hypercholesterolemic rats induced a significantly decrease in lipid peroxide concentrations and a significant increase in the GSH content, GSH-Px and GSH-ST activities in erythrocytes and liver. Conclusions: Long-term administration of vitamin E may play an important role in suppressing oxidative stress, and thus, may be useful for the prevention and/or early treatment of hypercholesterolemia. (C) 2002 Elsevier Science B.V. All rights reserved

INFLUENCE OF THYMIC FRACTION-5 ON ERYTHROCYTE (NA++K+)-ATPASE ACTIVITY IN HYPERCHOLESTEROLEMIC RABBITS

The effects of thymus fraction 5 injection on cholesterol, triglyceride and phospholipid levels in plasma and erythrocytes as well as on membrane-bound (Na+ + K+)-ATPase activity were investigated in rabbits fed a high-cholesterol diet for 3 months. While cholesterol feeding caused an increase in plasma and erythrocytes phospholipid levels, (Na+ + K+)-ATPase activity was found to be reduced. After high-cholesterol diet, the rabbits were given normal diet with or without thymosin F5 injections every other day for 21 days. Thymosin F5 treatment caused a significant decrease in plasma and erythrocyte phospholipid levels whereas membrane-bound (Na+ + K+)-ATPase activity was increased significantly. It is concluded that hypercholesterolemic lesions and the decreased erythrocyte ATPase activity may be eliminated by thymic extracts in rabbits

EFFECT OF THYMOSIN FRACTION-5 (F5) ON ERYTHROCYTE GLUTATHIONE AND LIPID PEROXIDE LEVELS IN HYPERCHOLESTEROLEMIC RABBITS

The effect of thymosin F5 injection on the erythrocyte glutathione levels were investigated in the rabbits fed 2% cholesterol diet for 4 weeks. Although the cholesterol rich diet caused a significant decrease in erythrocyte glutathione levels, erythrocyte lipid peroxide levels were increased considerably

The evaluation of lipid peroxidation and acute effect of octreotide on lipid peroxidation in patients with active acromegaly

Background: Although lipid peroxidation has been suggested to play a role in the etiology of many diseases, there is no report about its role in acromegaly in the literature. In the present study, we analyzed the basal levels of lipid peroxides (LPO) in newly diagnosed acromegalic patients, and to evaluate whether octreotide (OCT) has any effect on lipid peroxidation in these patients. Methods: Plasma lipid peroxide levels before and after acute OCT administration were measured in 12 newly diagnosed acromegalic patients. Blood samples were drawn at basal and 4, 8, and 24 h after octreotide injection (100 mug s.c.). Plasma concentrations of lipid peroxides were estimated from measurement of thiobarbituric acid reactive substance (TBARS), using 1,1,3,3-tetra-ethoxypropane as a standard. Results: This study shows that acromegalic patients have significantly higher basal plasma lipid peroxides levels compared to hours after OCT injection (p<0.001). Although a significant decrease was observed after 8 and 24 h in comparison to basal level (p<0.001), the lipid peroxide levels tended to increase at 24 h though still low when compared to basal level. Conclusion: Acromegalic patients have high basal lipid peroxide levels, which was significantly decreased after OCT administration. (C) 2003 Elsevier B.V. All rights reserved

THE ROLE OF THYMOSIN F5 ON ANEMIA IN HYPERCHOLESTEROLEMIC RABBITS

New Zealand White rabbits were made hypercholesterolemic by feeding a high cholesterol diet (20 g/kg diet) for 3 months. Plasma cholesterol concentrations were monitored as a function of time. At the end of 3 months, the plasma lipid levels, the whole blood, erythrocyte and haemoglobin-bound 2,3-DPG levels and leucocyte counts increased, whereas erythrocyte counts, hematocrit and haemoglobin levels decreased significantly in hypercholesterolemic rabbits. At the end of 3 months, the rabbits in the experimental group were divided into two groups. The first group was fed a standard diet for 21 days. The second group received 0.5 mg/kg thymosin F5 injection i.p. every other day for 21 days, After this period, the plasma lipid levels, the whole blood, erythrocyte and haemoglobin-bound 2,3-DPG levels, erythrocyte and leucocyte counts, hematocrit and haemoglobin levels were measured, Rabbits fed diets supplemented with thymosin F5 had markedly lower plasma lipid levels, erythrocyte counts, hematocrit and haemoglobin levels and enhanced leucocyte counts, but did not have significantly less whole blood, erythrocyte and haemoglobin-bound 2,3-DPG levels, We conclude tht thymosin F5 has lipid-lowering effects in hypercholesterolemic rabbits, The data further suggest that effects of thymosin F5 on haematological parameters are due to the cholesterol decrease and not to the direct regulatory mechanism