Beneficial effects of L-carnitine administration on blood glucose, lipids and oxidative stress markers in alloxan-induced diabetic rats

ABSTRACT

L-carnitine, a naturally occurring vitamin-like nutrient is widely distributed all over the body. It is frequently used as a dietary supplement by physically active people as it plays a great role in energy production. Currently, there is a renewed interest in carnitine, and many physicians advised it to treat a variety of conditions especially those associated with metabolic disorders as diabetes mellitus. It plays a role in both glucose and lipid metabolism as well as it may have an antioxidant effect. In diabetes mellitus, poor glycemic control, dyslipidemia and increased lipid peroxidation have been associated with poor diabetic outcome. The present work aimed to study the role of L- carnitine supplementation on glucose and lipid metabolism as well as to study its antioxidant effect in alloxan-induced diabetic rats. Also, a histological study of the pancreatic tissues of all studied animal groups have been done to determine if L-carnitine has a regenerative effect on the diabetic pancreatic B-cells. The study carried on 28 adult male albino rat, divided into 3 groups control group [group I], alloxan-induced diabetic rats [group II] and L-carnitine treated diabetic rats [group III]. After induction of diabetes in rats [by alloxan], L-carnitine was administered by IM daily injection of 100 mg/Kg body weight for 3 weeks. Serum levels of glucose, total cholesterol, triglyceride, lipid peroxide and nitric oxide were evaluated in all groups at the end of the experiment. Also, histological study of the pancreatic tissues of all studied animals groups have been done. After alloxan injection, all measured parameters were significantly increased in group II [p<0.001] in comparison to control group. Three, weeks after treatment of group III with L-carnitine, rats showed significant reduction in serum levels of glucose, total cholesterol and triglyceride [p<0.01] in comparison to non treated animals [group II]. In addition, there was significant reduction in serum levels of lipid peroxide and nitric oxide [p<0.01], Histological study of the pancreatic tissues showed morphological changes with degenerative destruction of islets of Langerhans of the pancreases of diabetic group [group II]. These degenerative changes did not showed any regeneration or improvement in the morphological structures of islets of Langerhans after L-carnitine treatment in group III. The study concluded that L-carnitine has a potential beneficial glucose and lipids lowering effects as well as an antioxidative effect in diabetic rats. Its glucose lowering effect is due to mechanism[s] other than regeneration of pancreatic B-cells, possibly may be through its antioxidant effects as well as increase cellular uptake and oxidation of glucose. So, [his cheap, relatively safe natural agent could be considered as a supplementary therapy for correction of the metabolic disorders associated with diabetes and to improve some of the neurological complications through its antioxidant effect. Further studies are needed before the efficacy of this treatment can be universally accepted