Comparing the Protective Effect of L-carnitine, Chromium, and Vitamin D with Metformin on Kidney Parameters, Lipid Profiles, and Antioxidant Indices in Streptozotocin-diabetic Rats

Introduction: Type 1 diabetes mellitus is believed to be caused by decline of insulin secretion because of destruction of the pancreatic β cell, which is characterized with symptoms such as hyperglycemia, polyuria, polydipsia, weight loss, and other symptoms. Due to the lack of sufficient data about protective effect of L-carnitine, chromium, and vitamin D as compared with metformin on biochemical indices in streptozotocin-diabetic rats, it seems necessary to determine the effects of these medications on diabetes. 
Materials and Methods: Sixty Wistar rats were divided into 12 diabetic and healthy groups, and 10 groups of witness, metformin )150 mg/kg(, L-carnitine )200 mg/kg(, and chromium )2 mg/kg(, vitamin D (0.06 μg) and a group treated with simultaneous combined therapy of L-carnitine, chromium, and vitamin D. Diabetes mellitus was induced by streptozotocin. Rats with glucose levels of more than 300 mg/dL were considered as diabetic. After 30 days of treatment, the serum concentrations of renal parameters, lipid profile, malondialdehyde, and activity of superoxide dismutase were measured in the studied groups. 
Results: Malondialdehyde had a significant decrease in all diabetic groups but an increase in nondiabetic metformin and L-carnitine groups (P < 0.05). In all groups, a significant reduction of triglyceride was observed (P < 0.05). Urea increased in the diabetic metformin and chromium treatment groups, whereas in the other groups it decreased (P < 0.05). Among diabetic metformin groups, a significant increase in serum creatinine was found (P < 0.05). High-density lipoprotein also decreased in the combined group of L-carnitine, chromium, and vitamin D (P < 0.05). Cholesterol in diabetic L-carnitine, chromium treatment, and combined group showed a significant decrease (P < 0.05). 
Conclusion: These data showed that all three drugs of L-carnitine, chromium, and vitamin D such as metformin seemed appropriate, which had the hypoglycemic, antilipidemic, and antioxidant effects.