Research Paper Volume 12, Issue 21 pp 21687—21705

Dexmedetomidine inhibits inflammatory response and autophagy through the circLrp1b/miR-27a-3p/Dram2 pathway in a rat model of traumatic brain injury

Hengchang Li1, , Chengxiang Lu1, , Wenfei Yao1, , Lixin Xu1, , Jun Zhou2, , Bin Zheng1, ,

  • 1 Department of Anesthesiology, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, Guangdong, China
  • 2 Department of Anesthesiology, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, China

Received: February 15, 2020       Accepted: July 14, 2020       Published: November 4, 2020
How to Cite

Copyright: © 2020 Li 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.


Circular RNAs (circRNAs) have a regulatory function on inflammation and autophagy, of which rno-circRNA_010705 (circLrp1b) appears to be significantly up-regulated following traumatic brain injury (TBI). Dexmedetomidine (DEX) shows improvement effects in TBI by inhibiting NLRP3/caspase-1. However, whether circLrp1b plays critical roles in DEX-mediated TBI attenuation and the underlying mechanisms remain unclear. After TBI was established in rats by controlled cortical impact (CCI) to cause brain trauma, they received an intracerebroventricular injection of lentiviral vector, followed by intraperitoneal injection of DEX. Administration of DEX ameliorated autophagy in rats following TBI, accompanied by up-regulated circLrp1b and Dram2 and down-regulated miR-27a-3p. DEX promoted the effects of circLrp1b in attenuating TBI-induced neurologic impairment, autophagy, and inflammation, which was significantly reversed by inhibition of miR-27a-3p or Dram2 overexpression. Mechanistically, northern blot and luciferase reporter assays indicated that circLrp1b up-regulated Dram2 expression by functioning as a sponge for miR-27a-3p to promote autophagy involved in TBI, which was reversed by DEX treatment. Collectively, this study demonstrated that DEX inhibits inflammatory response and autophagy involved in TBI in vivo through inactivation of the circLrp1b/miR-27a-3p/Dram2 signaling pathway.


circRNA: circular RNA; circLrp1b: rno-circRNA_010705; TBI: traumatic brain injury; DEX: dexmedetomidine; CCI: controlled cortical impact; mNSS: modified Neurological Severity Score; H&E: hematoxylin and eosin; TEM: transmission electron microscope; LPS: lipopolysaccharide; Dram2: DNA damage regulated autophagy modulator 2; SD: Sprague-Dawley; NC: negative control; qRT-PCR: real-time quantitative reverse transcriptase polymerase chain reaction; ELISA: enzyme-linked immunosorbent assay; gDNA: genomic DNA; WT: wild-type; MUT: mutant; SD: standard deviation.