Repression of long non-coding RNA MEG3 restores nerve growth and alleviates neurological impairment after cerebral ischemia-reperfusion injury in a rat model
Authors: Hong You
Dong You
Journal: Biomedicine & Pharmacotherapy (2019)
Discipline: PHARMACOLOGY & TOXICOLOGY
Keywords: Balance beam test; Cerebral ischemia-reperfusion injury; Fault-foot test; MEG3; Neurological impairment
Affiliations: Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, 130021, China., Department of Neurosurgery, The First Hospital of Jilin University, Changchun, 130021, China. Electronic address: .

Abstract:  Objective: This study was performed to investigate effect of long non-coding RNA (lncRNA) MEG3 on nerve growth and neurological impairment in a rat model after cerebral ischemia-reperfusion injury (IRI) through the Wnt/β-catenin signaling pathway. Methods: Rat models of middle cerebral artery occlusion (MCAO) were established to stimulate an environment of cerebral IRI. The modeled rats were subjected to negative control (NC), MEG3, si-MEG3, classical Wnt pathway inhibitor DKK1 or classical Wnt pathway activator LiCl to validate the effect of MEG3 on neurological impairment and nerve growth. Neurological deficit scoring, fault-foot test and balance beam test were performed to assess neurological impairment. TTC staining, dry-wet weight method and Evan's blue (EB) staining were employed to determine infarct area, water content of brain tissues and blood-brain barrier (BBB) permeability, respectively. Neuronal apoptosis and necrosis were observed by TUNEL staining and Fluoro-Jade C staining. ELISA was adopted to identify levels of nerve growth factors to identify neurogenesis conditions, including brain derived neurotrophic factor (BDNF), nerve growth factor (NGF) and basic fibroblast growth factor (bFGF). Nissl staining was used to detect the survival of neurons in brain tissues of rats. Western blot analysis was used to detect the expression of key proteins in Wnt/β-catenin signaling pathway in brain tissues. Results: High expression of MEG3 was identified in rat models of MACAO, the brain tissues of which manifested obvious neurological impairment, increased infarct area, water content, BBB permeability, accelerated neuronal apoptosis and necrosis, increased surviving neurons, upregulated expression of key proteins in Wnt/β-catenin signaling pathway and elevated levels of BDNF, NGF and bFGF. With the treatment of si-MEG3, the MEG3 expression was reduced; whereby, modeled rats showed ameliorated neurological impairment, reduced infarct area, water content, BBB permeability, neuronal apoptosis and necrosis and significantly enhanced neurogenesis. The treatment of MEG3 exhibited an opposite trend. After treatment with DKK1, the effect of si-MEG3 was reversed. After treatment with LiCl, the effect of MEG3 was reversed. Conclusion: Based on the findings of this study, down-regulation of lncRNA MEG3 expression enhanced nerve growth and alleviated neurological impairment of rats after cerebral IRI through the activation of the Wnt/β-catenin signaling pathway. 

Retracted: No

PubPeer comments:
 Fig 3E,  the hematoxylin-eosin staining to show pathological changes of brain tissues . ![file] Normal and Sham panels overlap. More to the point, the NC and MCAO panels (after a 180-deg flip) show fragments in common, but differently arranged. , 
 Fig 4A,  TUNEL staining to detect neuronal apoptosis in the brain tissues of rats, arrows indicate apoptotic cells . Normal panel (after a 90-deg rotation) has many of the same elements as the Sham panel, but there are differences, and rearrangements. ![file] , 
 Fig 5D,  Nissl staining for neuron survival in rats . ![file] The Sham and Normal panels are basically the same, apart from a vertical flip and rearrangement of some of the elements. , 
 Fig 4C. ![file] Fig 7G is left as an exercise for the reader. ![file] ,