Effects of triple antioxidant combination (vitamin E, vitamin C and ?-lipoic acid) with insulin on lipid and cholesterol levels and fatty acid composition of brain tissue in experimental diabetic and non-diabetic rats

Abstract

The aim of this research was to examine the effects of a triple antioxidant combination (vitamins E (VE) and C (VC) plus a-lipoic acid (LA)) on the total lipid and cholesterol levels and the fatty acid composition of brain tissues in experimental diabetic and nondiabetic rats. VE and LA were injected intraperitoneally (50 mg/kg) four times per week and VC was provided as a supplement dissolved in the drinking water (50 mg/kg). In addition, rats in the diabetes I and D + VELAVC groups were given daily by subcutaneous insulin injections (8 IU/kg), but no insulin was given to rats in the diabetes 2 group. The results indicate that the brain lipid levels in the D + VELAVC, diabetes I and diabetes 2 groups were higher than in the control group (P < 0.01). Total lipid was also higher in the non-diabetic rats treated with LA and VC. Total cholesterol was higher in the diabetes I and diabetes 2 groups (P < 0.05) than in controls. Cholesterol levels were similar in the D + VELAVC and LA groups but lower in the VC, VE and VELAVC groups of non-diabetic rats (P < 0.05 and P < 0.01). In respect of fatty acid composition, palmitic acid levels were lower in the diabetes 2 and non-diabetic VE groups than the control group (P < 0.05), but higher in the nondiabetic LA group (P < 0.05). Oleic acid (18:1 n-9) levels were lower in the diabetic and non-diabetic groups than the control group (P < 0.01), but higher in the non-diabetic LA group. Arachidonic acid (20:4 n-6) levels were similar in the diabetes 1, D + VELAVC and control groups (P > 0.05) but higher in the non-diabetic VE, VC, LA and VEVCLA groups (P < 0.05) and lower in the diabetes 2 group (P < 0.05). Docosahexaenoic acid (22:6 n-3) was elevated in the diabetes 2 and VEVCLA groups (P < 0.01, P < 0.05). In conclusion, the current study confirmed that treatment with a triple combination of VE, VC and LA protects the arachidonic acid level in the brains of diabetic and non-diabetic rats. (c) 2005 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.