SIRT3 confers protection against acute pulmonary embolism by anti-inflammation, anti-oxidative stress, anti-apoptosis: participation of AMPK/mTOR pathway.

Increasing studies have suggested that oxidative stress and inflammation play momentous roles in acute pulmonary embolism (APE). Honokiol, a bioactive biphenolic phytochemical substance, is known for its strong anti-oxidative and anti-inflammatory effects and here serves as an activator of sirtuin3 (SIRT3). The purposes of the study are to explore the effects of Honokiol on APE rats, and investigate whether the function of Honokiol is mediated by SIRT3 activation. In this study, the rats received a right femoral vein injection with dextran gel G-50 particles (12 mg/kg) to establish the APE model, which were administrated with Honokiol and/or selective SIRT3 inhibitor 3- (1H-1, 2, 3-triazol-4-yl) pyridine (3-TYP; 5 mg/kg) intraperitoneally. The data showed that SIRT3 activation by Honokiol attenuated the loss in lung function, ameliorated inflammatory response and oxidative damage as well as inhibited apoptosis in lung tissues of the rats with APE, which was reversed by 3-TYP. In addition, we found AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway might be activated by Honokiol but restrained by 3-TYP. These results indicated that Honokiol was capable of suppressing APE's adverse effects, which was diminished by SIRT3 suppression, implying that activation of SIRT3 might serve as a therapeutic method for APE.