Effect of Hydroxytyrosol on Prdx6 Expression in Diabetic Rat Liver

Aim: Oxidative stress caused by hyperglycemia, which is the most important complication of diabetes mellitus, causes liver damage. Hydroxytyrosol is a polyphenolic compound abundant in olive oil that protects the liver against oxidative damage. Peroxiredoxin 6 (Prdx6) is an anti-oxidative enzyme known to exist in the liver. The aim of this study was to investigate the effect of hydroxytyrosol on Prdx6 expression in diabetes-induced liver injury. Material and Methods: Male Wistar rats were grouped into four as the control group (n=10), hydroxytyrosol group (n=10), streptozotocin group (n=10), and hydroxytyrosol+streptozotocin group (n=10). Blood glucose levels of the animals were measured after streptozotocin injection and at the end of the experiment. The general structure of the liver was examined with a hematoxylin-eosin stain. Prdx6 protein expression was determined with an immunohistochemical method. Results: In the streptozotocin+hydroxytyrosol group, blood glucose level was found to be lower when compared with the streptozotocin group (p<0.001), and histopathological findings in hepatocytes were found to decrease. Prdx6 expression was found to be similar in the control and hydroxytyrosol groups (p=0.590). However, it was found to be higher in streptozotocin and streptozotocin+hydroxytyrosol groups (p<0.001). Prdx6 expression of the streptozotocin+hydroxytyrosol group was found lower than the streptozotocin group (p<0.001). Conclusion: Hydroxytyrosol, the anti-oxidative activity of which has been proven in many studies, was found to relieve blood glucose levels in diabetic rats, cause histopathological changes in hepatocytes, and decrease anti-oxidative Prdx6 expression. This decrease suggested that instead of inhibiting Prdx6, hydroxytyrosol reduced oxidative stress irrespective of Prdx6.