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.