Background: Diabetic nephropathy can lead to renal diseases; oxidative stress and mitochondrial
dysfunction have critical roles in its development.
Objectives: In this study, the effect of syringic acid (SYR), a natural phenolic acid, on diabetic
nephropathy and mitochondrial biogenesis was examined.
Methods: Diabetes was induced in rats by injecting streptozotocin. SYR (25, 50 and 100 mg/kg/day)
was orally administered for 6 weeks. SYR effects on factors, such as antioxidant activities and mRNA
expression level of mitochondrial biogenesis indexes, were evaluated.
Results: In SYR-treated rats, blood glucose and ALP level were significantly reduced. SYR increased
kidney GSH content in the diabetic group. Elevated renal catalase and superoxide dismutase activities in
diabetic rats were restored to normal levels after treatment. SYR significantly reduced the renal TBARS
level, which had increased in diabetic rats. This compound also significantly upregulated renal mRNA
expression of PGC-1α and NRF-1, and increased mtDNA/nDNA ratio in diabetic rats. These values
were reduced in the non-treated diabetic group. The results show improvement of histopathological
damages of kidney in the SYR treated group in comparison with the diabetic group.
Conclusion: According to the results, SYR alters renal antioxidant defense mechanisms. Also, it could
be considered as a novel approach by targeting mitochondria in renal diabetic complications.