Abstract
Human exposure to radio-therapeutic doses of gamma rays can produce late effects, which negatively affect cancer patients' quality of life, work prospects, and general health. This study was performed to explore the role of Piceatannol (PIC) in the process of "mitochondrial biogenesis" signaling pathway as possible management of disturbances induced in stressed animal model(s) either by gamma-irradiation (IR) or administration of reserpine (RES); as a mitochondrial complex-I inhibitor. PIC (10 mg/kg BW/day; orally) were given to rats for 7 days, after exposure to an acute dose of γ-radiation (6 Gy), or after a single reserpine injection (1 g/kg BW; sc). Compared to reserpine or γ-radiation, PIC has attenuated hepatic and renal mitochondrial oxidative stress denoted by the significant reduction in the content of lipid peroxides and NO with significant induction of SOD, CAT, GSH-PX, and GR activities. PIC has also significantly alleviated the increase of the inflammatory markers, TNF-α and IL-6 and apoptotic markers, cytochrome c, and caspase-3. The decrease of oxidative stress, inflammation, and apoptotic responses were linked to a significant amelioration in mitochondrial biogenesis demonstrated by the increased expression and proteins' tissue contents of SIRT1/p38-AMPK, PGC-1α signaling pathway. The results are substantiated by the significant amelioration in mitochondrial function verified by the higher levels of ATP content, and complex I activity, besides the improvement of hepatic and renal functions. Additionally, histopathological examinations of hepatic and renal tissues showed that PIC has modulated tissue architecture after reserpine or gamma-radiation-induced tissue damage. Piceatannol improves mitochondrial functions by regulating the oxidant/antioxidant disequilibrium, the inflammatory and apoptotic responses, suggesting its possible use as adjuvant therapy in radio-therapeutic protocols to attenuate hepatic and renal injuries.