Evaluation of Antioxidant Effects of Coenzyme Q10 against Hyperglycemia-Mediated Oxidative Stress by Focusing on Nrf2/Keap1/HO-1 Signaling Pathway in the Liver of Diabetic Rats.

Abstract

Hyperglycemia-induced oxidative stress can damage the liver and lead to diabetes complications. Coenzyme Q10 (CoQ-10) reduces diabetes-related oxidative stress. However, its molecular mechanisms are still unclear. This study aimed to examine CoQ-10's antioxidant capabilities against hyperglycemia-induced oxidative stress in the livers of diabetic rats, specifically targeting the Nrf2/Keap1/ARE signaling pathway. This study was conducted between 2020-2021 at Arak University of Medical Sciences. A total of 30 male adult Wistar rats (8 weeks old) weighing 220-250 g were randomly assigned to five groups (n=6 in each group): control healthy, sesame oil (CoQ-10 solvent), CoQ-10 (10 mg/Kg), diabetic, and diabetic+CoQ-10. Liver oxidative stress indicators, including malondialdehyde, catalase, glutathione peroxidase, and glutathione, were estimated using the spectrophotometry method. Nrf2, Keap1, HO-1, and NQO1 gene expressions were measured using real-time PCR tests in the liver tissue. All treatments were conducted for 6 weeks. Statistical analysis was performed using SPSS software. One-way ANOVA followed by LSD's or Tukey's post hoc tests were used to compare the results of different groups. P<0.05 was considered statistically significant. The findings showed that induction of diabetes significantly increased Keap1 expression (2.1±0.9 folds, P=0.01), and significantly inhibited the mRNA expression of Nrf2 (0.38±0.2 folds, P=0.009), HO-1 (0.27±0.1 folds, P=0.02), and NQO1 (0.26±0.1 folds P=0.01), compared with the healthy group. In the diabetic group, the activity of glutathione peroxidase, catalase enzymes, and glutathione levels was decreased with an increase in malondialdehyde level. CoQ-10 supplementation significantly up-regulated the expressions of Nrf2 (0.85±0.3, P=0.04), HO-1 (0.94±0.2, P=0.04), NQO1 (0.88±0.5, P=0.03) genes, and inhibited Keap1 expression (1.1±0.6, P=0.02). Furthermore, as compared to control diabetic rats, CoQ-10 ameliorated oxidative stress by decreasing malondialdehyde levels and increasing catalase, glutathione peroxidase activities, and glutathione levels in the liver tissues of the treated rats in the treatment group. The findings of this study revealed that CoQ-10 could increase the antioxidant capacity of the liver tissue in diabetic rats by modulating the Nrf2/Keap1/HO-1/NQO1 signaling pathway.