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

The aim of this research was to examine the effects of a triple antioxidant combination (vitamins E (VE) and C (VC) plus alpha-lipoic acid (LA)) on the total lipid and cholesterol levels and the fatty acid composition of brain tissues in experimental diabetic and non-diabetic 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 1 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 1 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 1 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 non-diabetic 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.