Morphological changes in the kidney tissue of rats with experimental diabetes mellitus and during correction with metformin and modulators of hydrogen sulfide metabolism

Abstract

Annotation. Metformin is widely used for pharmacocorrection of diabetic nephropathy in type 2 diabetes mellitus. However, the mechanisms of the protective effect of metformin on the kidneys remain unclear, in particular, the contribution of the hydrogen sulfide system to metformin’s nephroprotective effect is unknown. Therefore, the aim of our study was to assess the role of metformin and its combination with modulators of hydrogen sulfide metabolism in the correction of histological changes in the kidneys of streptozotocin-induced diabetic rats. The studies were performed on 30 white non-linear male rats, which were divided into five groups: 1 group - control; group 2 – animals with experimental diabetes, which was initiated by a single intraperitoneal injection of streptozotocin (40 mg/kg of weight) in 0.1 M citrate buffer (pH 4.5); Group 3 - animals with experimental diabetes, which were treated with metformin (500 mg/kg/day, intragastrically) from the 3rd to the 28th day; Group 4 - animals with diabetes mellitus, which, along with metformin, were administered NaHS (56 μmol/kg/day, intragastrically); Group 5 - animals with diabetes mellitus, which, along with metformin, were administered propargylglycine (442 μmol/kg/day, intragastrically). Histological examinations were performed according to generally accepted methods using an Olympus BX-41 light microscope (Olympus Europe GmbH, Japan). It was found that animals with experimental diabetes develop nephrosclerosis and glomerular hypertrophy, damage to the endothelium of kidney vessels, interstitial inflammation, and edema, and dystrophic and necrobiotic changes in the glomeruli. The administration of metformin to diabetic animals reduced the severity of nephrosclerosis, glomerular hypertrophy, destruction of vascular endotheliocytes, inflammation, and damage to the glomerular apparatus. The use of the hydrogen sulfide donor NaHS increased the nephroprotective activity of metformin, while the introduction of the hydrogen sulfide synthesis inhibitor- propargylglycine, significantly reduced the protective effect of metformin on the kidneys. The obtained results of the histological examination justify the feasibility of implementation of a hydrogen sulfide donor in order to potentiate the renoprotective effect of metformin.