Steviol glycosides, L-arginine, and chromium(III) affect trace element status in diabetic rats

Background. Iron, zinc, copper, and chromium status is often disturbed in the course of metabolic diseases, including type 2 diabetes mellitus. This brings about alterations and abnormalities in the absorption, distribution, and excretion of certain elements and in turn, is responsible for further progression of the disease. This study aimed to evaluate the effects of a high-fat diet supplemented with a combination of steviol glycosides (stevioside or rebaudioside A), L-arginine (two levels), and chromium(III) (two levels) on trace element (Fe, Zn, Cu, Cr) content in the liver and kidneys of rats with induced type 2 diabetes.
Materials and methods. The experiment was carried out on 110 rats, of which 100 were induced with mild type 2 diabetes with high-fat diet feeding and intraperitoneal streptozotocin injection. Afterward, the diabetic animals were divided into 10 groups and received either a high-fat diet, a high-fat diet with metformin (0.3%), or a high-fat diet supplemented with a combination of steviol glycosides (stevioside or rebaudioside A, 2.5%), L-arginine (2% or 4%), and chromium(III) (0.001% or 0.005%) for 6 weeks. The Fe, Zn, Cu, and Cr content in tissues was determined after microwave mineralization of samples and then using the atomicabsorption spectroscopy (AAS) method.
Results. Induced hyperglycemia disturbed several tissular trace element levels in the liver and kidneys of type 2 diabetic rats. Combined supplementary factors, such as the type of steviol glycoside or levels of either
L-arginine and/or chromium(III), were able to mitigate some alterations of trace elements, while some particular combinations of experimental factors even increased certain trace elements content in the analyzed internal organs of rats.
Conclusions. Mild hyperglycemia disturbs trace element (Zn, Cr) balance by shifting trace element concentrations in the critical organs (liver, kidneys) in type 2 diabetes rats. Supplementary agents can independently, or in certain combinations, mitigate some trace element alterations or even cause further changes in their concentrations in the liver or the kidneys. The metabolic significance of these alterations is not fully understood and warrants further studies.