Protective Effect of L-carnitine on Metabolic Disorders, Oxidative Stress, Antioxidant Status and Inflammation in a Rat Model of Insulin Resistance

Abstract

The high-fructose diet induces insulin resistance, hyperinsulinaemia, hyperglycemia, alterations in lipid metabolism, and oxidative stress in rat tissues which Oxidative stress plays a vital role in pathology associated with insulin resistance. The present study was aimed to explore the effect of L-carnitine (CAR) on insulin resistance, inflammation, oxidative stress, antioxidant status, and lipid metabolism in male rats fed with high fructose diet. Insulin resistance was induced by feeding high fructose diet (60 g/100 g). sixty male albino rats were divided into four groups containing 15 rats each. Group Ι:( Control group ) rats received the control diets. Group II (fructose-fed group) rats received fructoseenriched diet (60 g /100g). Group III: (fructose + CAR group) animals received high fructose diet and were administered CAR (300 mg/Kg body weight /day,orally). Group IV: (control +CAR group) rats received the control diet and were administered CAR. After 45 and 60 days of treatment blood samples and liver tissue were collected for determination of serum glucose, insulin, insulin resistance, pyruvate, lactate, leptin, total cholesterol, triacylglycerols, phospholipids, free fatty acids, sialic acid, tumor necrosis factorα (TNFα), interleukin-6 (IL-6) and nitric oxide in addition to Lmalondialdehyde (L-MDA). Moreover, antioxidant enzymes (SOD,CAT and GPx) in liver tissues were also determined. The obtained results revealed that, high fructose diet induce a significant increased in serum glucose, insulin, insulin resistance, lipid profiles, pyruvate, lactate, lipten, TNF-α, IL-6, sialic acid, MDA and nitric oxide concentrations and decrease serum phospholipids with marked reduction in CAT, SOD and GpX concentrations in liver tissues compared to rats fed normal diet. L-carnitine treatment to high fructose fed rats reduced the effects of fructose and associated with significant normalization of all serum parameters level and was able to improve dyslipidemia, inflammation and insulin resistance, attenuated the increased MDA and enhanced antioxidant status in liver tissues. These results suggest that, Lcarnitine is effective in improving the high fructose induced oxidative stress, inflammation and insulin resistance in male rats. Also, the administration of of L-carnitine to rats fed a high fructose diet prevents the development of oxidative stress and its associated complications include hyperglycemia , hyperinsulinemia and dyslipidemia.