Syringic acid improves oxidative stress and mitochondrial biogenesis in the liver of streptozotocin-induced diabetic rats

ABSTRACT

Objective: To determine the effects of syringic acid on hepatic damage in diabetic rats. Methods: Diabetes was induced by streptozotocin. Diabetic rats were given syringic acid at doses of 25, 50 and 100 mg/kg by oral gavage for 6 weeks. Syringic acid effects on the liver were evaluated by examination of plasma biochemical parameters, and pathological study. In addition, biomarkers of lipid peroxidation and antioxidant status of liver tissues were assessed. Real time-PCR was performed to investigate the mRNA expression levels of mitochondrial biogenesis indices in different groups. Results: Syringic acid significantly attenuated the increase in most of plasma biochemical parameters in diabetic rats. Moreover, syringic acid treatment increased the catalase activity while it reduced the superoxide dismutase activity and hepatic malondialdehyde level in diabetic rats. There was no difference between the glutathione content of the treated and untreated groups. These findings were supported by alleviation of histopathological damages in the syringic acid-treated groups compared to the untreated diabetic group. Syringic acid also significantly up-regulated the hepatic mRNA expression of PGC-1a, NRF-1, and NRF-2 and increased the mtDNA/nDNA ratio in diabetic rats. Conclusions: Syringic acid can be considered as a suitable candidate against hepatic complications since it can reduce oxidative damages in diabetic cases. Furthermore, it has the potential of targeting hepatic mitochondria in diabetes.