Rutin Protects Pancreatic Islets Against Methylglyoxal-Induced Oxidative Stress and Elevates Insulin Secretion

Rutin Improves Islets Damage

Abstract

Objective: Hyperglycemia is the main characteristic of diabetes, which leads to complications, including oxidative stress. Pancreatic β-cells are susceptible to damage against oxidative stress, which results in a disruption in insulin secretion. The current study focused on the antioxidant features of rutin (Rtn) flavonoid to prevent methylglyoxal (MG) induced oxidative damage in pancreatic islets isolated from mice.

Methods: After isolating islets from twenty-four male mice, we conducted two experimental parts, 1: with and 2: without exposure of islets to MG. Experiments were carried out in both culture mediums with 5.6 and 16.7 mM glucose concentrations. The islets were transferred to the culture medium and exposed to different substances. In the end, insulin secretion, antioxidant enzyme activities, and malondialdehyde concentration were investigated by ELISA assay.

Results: The reduced levels of insulin in MG-exposed islets (P=0.01, P<0.001 in 5.6 and 16.7 mM glucose concentration, respectively) were reversed by Rtn treatment. MG increased malondialdehyde levels in 5.6 and 16.7 mM glucose concentrations (P<0.001) (P=0.005). Also, we observed a remarkable decrease in the activities of catalase, superoxide dismutase, and glutathione peroxidase due to 300 μM MG exposure in islets (in 5.6 and 16.7 mM glucose concentration). Rtn at doses 1 and 2 µM significantly reduced malondialdehyde levels. Moreover, Rtn had beneficial effects on antioxidant activities.

Conclusions: Rtn significantly protected pancreatic islets by reducing lipid peroxidation and enhancing antioxidant activity. Also, the decreased insulin levels in MG-exposed islets were effectively restored in the Rtn-treated groups.