Melatonin and L-carnitin improves endothelial disfunction and oxidative stress in Type 2 diabetic rats

Abstract

Vascular dysfunction is thought to play a major role in the development of diabetic cardiovascular disease. The roles of endothelial dysfunction, oxidative stress, and dyslipidemia will be considered. Melatonin as well as L-carnitine were shown to possess strong antioxidant properties. Diabetes induced with high fat diet (for 8 weeks) and multipl low doses intraperitoneal injection of STZ (twice, 30 mg/kg/d i.p). The diabetic animals were randomly assigned to one of the experimental groups as follows: Control group (C), high fat diet (HFD), STZ-induced diabetic group (HFD+STZ) , HFD+STZ diabetic group received melatonin (10 mg/kg/d i.p), HFD+STZ diabetic group received L-carnitine (0.6 g/kg/d i.p), and HFD+STZ diabetic group received glibenclamide (5 mg/kg/d, oral). The serum fasting blood glucose, insulin, total cholesterol, HDL- cholesterol, LDL-cholesterol, triglyceride and malondialdehyde (MDA) levels were tested. Acetylcholine induced endothelium-dependent relaxation and sodium nitroprusside induced endothelium-independent relaxation were measured in aortas for estimating endothelial function. Also, glutathione peroxidase (GPx), superoxide dismutase (SOD) and nitric oxide (NO) levels activities were determined in rat liver. According to our results melatonin and L-carnitine treatment decreased fasting blood glucose, total cholesterol, and LDL levels. MDA levels significantly decreased with the melatonin treatment whereas SOD levels were not significantly changed between the groups. The results suggest that especially melatonin restores the vascular responses and endothelial dysfunction in diabetes.

Carnitine effects on serum and pancreas inflammatory response in diabetic rats

“…Intraperitoneal administration of 600 mg/kg/ day of L-carnitine attenuated serum glucose, and lipid profile in a rat model of type 2 diabetes [27]. Previous ly, we showed that 600 mg/kg/day of oral L-carnitine administration (5 weeks) reduced serum glucose and normalized insulin in STZ-induced diabetic rats [15].…”

“…Previous ly, we showed that 600 mg/kg/day of oral L-carnitine administration (5 weeks) reduced serum glucose and normalized insulin in STZ-induced diabetic rats [15]. Other studies also evaluated the therapeutic effects of L-carnitine in diabetic models [15,27,28]. We found that high doses of L-carnitine (200 and 300 mg/kg/day; i.p.…”

“…L-carnitine glucose-lowering effects in diabetes is controversial. several studies showed glucose-lowering effect upon L-carnitine administration but some other studies were not successful to show this hypoglycemic property of L-carnitine [15,27,[29][30][31][32]. This controversy could be contributed to the route of L-carnitine administration in different studies.…”

Melatonin reduces lens oxidative stress level in STZ-induced diabetic rats through supporting glutathione peroxidase and reduced glutathione values

“…Melatonin (N-acetyl-5-methoxytryptamine) hormone is mainly secreted by pineal gland and most of physiological functions in the body are affected by the hormone (Ekmekcioglu, 2006;Sharafati-Chaleshtori et al, 2017). A main role of the hormone in the body is antioxidant role and evidences from studies proved a key role of melatonin in the ROS production through regulation of glucose metabolism in the pathogenesis of diabetes (Salmanoglu et al, 2016;Kahya et al, 2017). Positive role of melatonin on blood antioxidants levels such as reduced glutathione (GSH) level and glutathione peroxidase (GPx) activity in several diseases except diabetes was reported (Urata et al, 1999;Reiter et al, 2001).…”

L-carnitine ameliorates peripheral neuropathy in diabetic mice with a corresponding increase in insulin‑like growth factor‑1 level

“…L-carnitine (β-hydroxy-γ-N-trimethylaminobutyric acid; LC), the biologically active form of carnitine, is an amino acid-like agent involved in the transit of long chain fatty acids that is synthesized in various tissues (7) and serves an impor-and serves an important role in fatty acid oxidation (8). Bach et al (9) reported that the skeletal muscle, heart, intestines, testis and in particular liver, can hydroxylate γ-butyrobetaine into carnitine.…”