Polydatin ameliorates injury to the small intestine induced by hemorrhagic shock via SIRT3 activation-mediated mitochondrial protection

Background: Previously, we demonstrated that sirtuin (SIRT) 1 plays vital roles in the small intestine (SI), protecting against severe hemorrhagic shock (HS), and that polydatin (PD) can attenuate SI injury via SIRT1 activation. Objective: To explore the role of SIRT3 and mitochondria in SI injury after HS, and explore SIRT3 as a therapeutic target of PD in HS. Methods: An H2O2-induced model of oxidative stress and an HS model were created in IEC-6 cells and Sprague-Dawley rats, respectively. Protein content and activity of SIRT1/3 and SOD2, acetylated-SOD2 level, and mitochondrial morphology/function were determined. Results: Expression and activity of SIRT1/3 were reduced in SI tissue and IEC-6 cells after HS or oxidative stress, accompanied by an increased acetylated-SOD2 level and damaged mitochondria. Treatment with PD or resveratrol restored SIRT1/3 activity considerably, restored SIRT1/3 expression slightly, and reduced acetylated-SOD2 levels, which lead to elevated SOD2 activity and ameliorated mitochondrial function. The addition of 3-TYP (SIRT3 inhibitor) partially blocked the mitochondrial-protective effects of PD, but did not affect increased SIRT1 activity. Conclusions: The SIRT3-SOD2 signaling pathway is involved in mitochondrial dysfunction induced by HS. PD attenuates mitochondrial dysfunction via activation of the SIRT3-SOD2 pathway, and may be a new approach for HS treatment.