Honokiol ameliorates pyroptosis in intestinal ischemia‑reperfusion injury by regulating the SIRT3‑mediated NLRP3 inflammasome.

Abstract

Intestinal ischemia‑reperfusion (IIR) injury is caused by the restoration of blood supply after a period of ischemia. It occurs in numerous clinical pathologies, such as intestinal obstruction, incarcerated hernia and septic shock, with mortality rates of 50‑80%. Honokiol (HKL), isolated from the herb Magnolia officinalis, is a biphenolic natural product with antioxidative, antibacterial, antitumor and anti‑inflammatory properties. Additionally, HKL has protective effects in ischemia‑reperfusion injuries, but its role and specific mechanisms in IIR injury are yet to be elucidated. In the present study, the superior mesenteric artery was ligated in rats to establish an IIR model. Hematoxylin and eosin staining and ELISA revealed that HKL administration ameliorated IIR‑induced injury in rats, which was demonstrated by a reduced destruction to the intestinal mucosa, as well as a reduced serum intestinal fatty acid‑binding protein concentration and Chiu's score in 10 mg/kg HKL treated IIR‑induced rats compared with those without HKL treatment. Additionally, immunohistochemical (IHC) staining and western blotting revealed that the occludin and tight junction protein 1 protein levels were increased in the 10 mg/kg HKL treated IIR‑induced rats compared with those without HKL treatment. Furthermore, an in vitro hypoxia/reoxygenation (H/R) cell model was established using IEC‑6 cells. Cell Counting Kit‑8 and lactate dehydrogenase (LDH) assays indicated that HKL mitigated the H/R‑inhibited cell viability and decreased the LDH levels in cell supernatants. Mechanistically, immunofluorescent (IF) staining and western blotting revealed that HKL inhibited H/R‑triggered pyroptosis. Furthermore, Mito‑Tracker, mitochondrial membrane potential and MitoSOX staining as well as western blotting revealed that reducing mitochondrial reactive oxygen species (ROS) inhibited the H/R‑induced pyroptosis by mitigating mitochondrial dysfunction. In the present H/R cell model, HKL improved the mitochondrial function by increasing the expression of sirtuin 3 (SIRT3), while IF staining and western blotting indicated that silencing SIRT3 notably reduced the beneficial effect of HKL on pyroptosis. In addition, IHC staining and western blotting revealed that HKL treatment mitigated the IIR‑induced pyroptosis in rats. Therefore, HKL treatment may mitigate IIR‑induced mitochondrial dysfunction and reduce mitochondrial ROS production by increasing the expression of SIRT3 protein, potentially resulting in an inhibition of pyroptosis during IIR.