IMR Press / FBL / Volume 28 / Issue 12 / DOI: 10.31083/j.fbl2812323
Open Access Original Research
Dexmedetomidine Alleviates Ischemia/Reperfusion-Associated Acute Kidney Injury by Enhancing Autophagic Activity via the α2-AR/AMPK/mTOR Pathway
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1 Department of Intensive Care Unit, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, 215008 Suzhou, Jiangsu, China
2 Suzhou Clinical Medical Center of Critical Care Medicine, 215001 Suzhou, Jiangsu, China
3 Department of Nephrology, The First Affiliated Hospital of Soochow University, 215006 Suzhou, Jiangsu, China
4 Department of Physiology and Neurosciences, Medical College of Soochow University, 215123 Suzhou, Jiangsu, China
*Correspondence: yangax_2000@hotmail.com (Ai-Xiang Yang); zhangguoxing@suda.edu.cn (Guo-Xing Zhang)
These authors contributed equally.
Front. Biosci. (Landmark Ed) 2023, 28(12), 323; https://doi.org/10.31083/j.fbl2812323
Submitted: 20 April 2023 | Revised: 24 June 2023 | Accepted: 28 June 2023 | Published: 1 December 2023
Copyright: © 2023 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.
Abstract

Background: Dexmedetomidine (DEX) reportedly protects against ischemia-reperfusion (I/R) injury and associated damage to the kidneys, but the underlying mechanisms have yet to be established. Methods: Unilateral nephrectomy was performed in Wistar rats, and the remaining kidney was clamped for 1 h prior to reperfusion to establish an experimental model system. These animals were then randomized into Sham, DEX + Sham, DEX + I/R, ATI (Altepamizole, α2-adrenergic receptor inhibitor) + DEX + I/R, and 3-MA (3-methyladenine, autophagy inhibitor) + DEX + I/R groups. Serum renal function biomarkers, acute kidney injury (AKI) histopathological scores, serum inflammatory factors, redox biomarkers, markers of autophagic flux, and autophagosome numbers were assessed. Levels of proteins related to the autophagic pathway, including mTOR and AMPK, were also analyzed. Results: Serum creatinine and urea nitrogen levels in the I/R group were significantly elevated over those in sham control rats, as were AKI scores, serum inflammatory cytokine concentrations (IL-6, IL-1β, and TNF-α), and serum levels of the oxidative stress biomarker malondialdehyde (MDA). All of these parameters were significantly reduced in the DEX + I/R group relative to I/R model rats. I/R group rats also exhibited significant decreases in renal levels of autophagic flux-related biomarkers and autophagosome numbers relative to sham controls, while DEX administration partially restored normal autophagic flux in these rats. Acute I/R also suppress the expression of AMPK in the kidney while increasing mTOR expression, and DEX reversed these effects. The beneficial impact of DEX on I/R-associated AKI was ablated by ATI or 3-MA administration. Conclusions: These analyses provide strong evidence for the ability of DEX to protect against I/R-associated AKI via the α2-AR/AMPK/mTOR pathway-mediated enhancement of autophagic activity.

Keywords
acute kidney injury
renal ischemia and reperfusion
dexmedetomidine
autophagy
α2-AR/AMPK/mTOR pathway
Funding
81970422/National Natural Science Foundation of China
GSKY20210201/The research project of Gusu School, Nanjing Medical University
Figures
Fig. 1.
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