Research Paper Volume 13, Issue 12 pp 16105—16123

Melatonin protects against focal cerebral ischemia-reperfusion injury in diabetic mice by ameliorating mitochondrial impairments: involvement of the Akt-SIRT3-SOD2 signaling pathway

Lian Liu1, , Quan Cao2, , Wenwei Gao3, , Bingyu Li1, , Zhongyuan Xia1, , Bo Zhao1, ,

  • 1 Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, China
  • 2 Department of Ultrasound Imaging, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, China
  • 3 Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, China

Received: February 2, 2021       Accepted: May 17, 2021       Published: June 11, 2021
How to Cite

Copyright: © 2021 Liu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Diabetic patients are more vulnerable to cerebral ischemia-reperfusion (CIR) injury and have a worse prognosis and higher mortality after ischemic stroke than non-diabetic counterparts. Melatonin can exert neuroprotective effects against CIR injury in nondiabetic animal models. However, its effects on diabetic CIR injury and the underlying mechanisms remain unclarified. Herein, we found that melatonin administration improved neurological deficit, cerebral infarct volume, brain edema, and cell viability, reduced mitochondrial swelling, reactive oxygen species generation, and cytoplasmic cytochrome C release, and increased mitochondrial antioxidant enzymes activities, adenosine triphosphate production, and mitochondrial membrane potential in both streptozotocin-induced diabetic mice and high glucose-treated HT22 cells. Importantly, melatonin also activated protein kinase B (Akt) and sirtuin 3 (SIRT3)/superoxide dismutase 2 (SOD2) signaling and upregulated mitochondrial biogenesis-related transcription factors. However, these effects were largely attenuated by LY294002 (a specific Akt signaling blocker) administration. Additionally, 3-TYP (a selective SIRT3 inhibitor) and SIRT3 siRNA inhibited the above protective effects of melatonin as well as the upregulation of SIRT3 and the decrease of SOD2 acetylation but did not affect the p-Akt/Akt ratio. Overall, we demonstrate that melatonin can alleviate CIR injury in diabetic mice by activating Akt-SIRT3-SOD2 signaling and subsequently improving mitochondrial damage.


Akt: protein kinase B; ANOVA: one-way analysis of variance; ATP: adenosine triphosphate; ac-SOD2: acetylated-SOD2; CIR: cerebral ischemia-reperfusion; CAT: catalase; CCK-8: cell counting kit-8; Cyt-cyto C: cytoplasmic cytochrome C; DMEM: Dulbecco’s modified Eagle’s medium; FBS: fetal bovine serum; MCAO: middle cerebral artery occlusion; MDA: malonaldehyde; MMP: mitochondrial membrane potential; NRF1: nuclear respiratory factor 1; ROS: reactive oxygen species; STZ: streptozotocin; SPF: specific-pathogen-free; SIR: simulated ischemia-reperfusion; SIRT3: sirtuin 3; SOD: superoxide dismutase; SEM: standard error of mean; TTC: triphenyl tetrazolium chloride; TFAM: mitochondrial transcription factor A.