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Chen X, Chen A, Wei J, Huang Y, Deng J, Chen P, Yan Y, Lin M, Chen L, Zhang J, Huang Z, Zeng X, Gong C, Zheng X. Dexmedetomidine alleviates cognitive impairment by promoting hippocampal neurogenesis via BDNF/TrkB/CREB signaling pathway in hypoxic-ischemic neonatal rats. CNS Neurosci Ther 2024; 30:e14486. [PMID: 37830170 PMCID: PMC10805444 DOI: 10.1111/cns.14486] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 10/14/2023] Open
Abstract
AIMS Dexmedetomidine (DEX) has been reported to alleviate hypoxic-ischemic brain damage (HIBD) in neonates. This study aimed to investigate whether DEX improves cognitive impairment by promoting hippocampal neurogenesis via the BDNF/TrkB/CREB signaling pathway in neonatal rats with HIBD. METHODS HIBD was induced in postnatal day 7 rats using the Rice-Vannucci method, and DEX (25 μg/kg) was administered intraperitoneally immediately after the HIBD induction. The BDNF/TrkB/CREB pathway was regulated by administering the TrkB receptor antagonist ANA-12 through intraperitoneal injection or by delivering adeno-associated virus (AAV)-shRNA-BDNF via intrahippocampal injection. Western blot was performed to measure the levels of BDNF, TrkB, and CREB. Immunofluorescence staining was utilized to identify the polarization of astrocytes and evaluate the levels of neurogenesis in the dentate gyrus of the hippocampus. Nissl and TTC staining were performed to evaluate the extent of neuronal damage. The MWM test was conducted to evaluate spatial learning and memory ability. RESULTS The levels of BDNF and neurogenesis exhibited a notable decrease in the hippocampus of neonatal rats after HIBD, as determined by RNA-sequencing technology. Our results demonstrated that treatment with DEX effectively increased the protein expression of BDNF and the phosphorylation of TrkB and CREB, promoting neurogenesis in the dentate gyrus of the hippocampus in neonatal rats with HIBD. Specifically, DEX treatment significantly augmented the expression of BDNF in hippocampal astrocytes, while decreasing the proportion of detrimental A1 astrocytes and increasing the proportion of beneficial A2 astrocytes in neonatal rats with HIBD. Furthermore, inhibiting the BDNF/TrkB/CREB pathway using either ANA-12 or AAV-shRNA-BDNF significantly counteracted the advantageous outcomes of DEX on hippocampal neurogenesis, neuronal survival, and cognitive improvement. CONCLUSIONS DEX promoted neurogenesis in the hippocampus by activating the BDNF/TrkB/CREB pathway through the induction of polarization of A1 astrocytes toward A2 astrocytes, subsequently mitigating neuronal damage and cognitive impairment in neonates with HIBD.
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Affiliation(s)
- Xiaohui Chen
- Department of AnesthesiologyShengli Clinical Medical College of Fujian Medical University, Fujian Provincial HospitalFuzhouChina
| | - Andi Chen
- Department of AnesthesiologyShengli Clinical Medical College of Fujian Medical University, Fujian Provincial HospitalFuzhouChina
| | - Jianjie Wei
- Department of AnesthesiologyShengli Clinical Medical College of Fujian Medical University, Fujian Provincial HospitalFuzhouChina
| | - Yongxin Huang
- Department of AnesthesiologyShengli Clinical Medical College of Fujian Medical University, Fujian Provincial HospitalFuzhouChina
| | - Jianhui Deng
- Department of AnesthesiologyShengli Clinical Medical College of Fujian Medical University, Fujian Provincial HospitalFuzhouChina
| | - Pinzhong Chen
- Department of AnesthesiologyShengli Clinical Medical College of Fujian Medical University, Fujian Provincial HospitalFuzhouChina
| | - Yanlin Yan
- Department of AnesthesiologyShengli Clinical Medical College of Fujian Medical University, Fujian Provincial HospitalFuzhouChina
| | - Mingxue Lin
- Department of AnesthesiologyShengli Clinical Medical College of Fujian Medical University, Fujian Provincial HospitalFuzhouChina
| | - Lifei Chen
- Department of AnesthesiologyShengli Clinical Medical College of Fujian Medical University, Fujian Provincial HospitalFuzhouChina
| | - Jiuyun Zhang
- Fujian Provincial Key Laboratory of Emergency MedicineFuzhouChina
| | - Zhibin Huang
- Department of AnesthesiologyShengli Clinical Medical College of Fujian Medical University, Fujian Provincial HospitalFuzhouChina
| | - Xiaoqian Zeng
- Department of AnesthesiologyShengli Clinical Medical College of Fujian Medical University, Fujian Provincial HospitalFuzhouChina
| | - Cansheng Gong
- Department of AnesthesiologyShengli Clinical Medical College of Fujian Medical University, Fujian Provincial HospitalFuzhouChina
| | - Xiaochun Zheng
- Department of AnesthesiologyShengli Clinical Medical College of Fujian Medical University, Fujian Provincial HospitalFuzhouChina
- Fujian Provincial Key Laboratory of Emergency MedicineFuzhouChina
- Fujian Emergency Medical Center, Fujian Provincial Key Laboratory of Critical Care MedicineFujian Provincial Co‐Constructed Laboratory of “Belt and Road”FuzhouChina
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Smiley JF, Bleiwas C, Marino BM, Vaddi P, Canals-Baker S, Wilson DA, Saito M. Estimates of total neuron number show that neonatal ethanol causes immediate and lasting neuron loss in cortical and subcortical areas. Front Neurosci 2023; 17:1186529. [PMID: 37205048 PMCID: PMC10185770 DOI: 10.3389/fnins.2023.1186529] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 04/13/2023] [Indexed: 05/21/2023] Open
Abstract
In neonatal brain development there is a period of normal apoptotic cell death that regulates adult neuron number. At approximately the same period, ethanol exposure can cause a dramatic spike in apoptotic cell death. While ethanol-induced apoptosis has been shown to reduce adult neuron number, questions remain about the regional selectivity of the ethanol effect, and whether the brain might have some capacity to overcome the initial neuron loss. The present study used stereological cell counting to compare cumulative neuron loss 8 h after postnatal day 7 (P7) ethanol treatment to that of animals left to mature to adulthood (P70). Across several brain regions we found that the reduction of total neuron number after 8 h was as large as that of adult animals. Comparison between regions revealed that some areas are more vulnerable, with neuron loss in the anterior thalamic nuclei > the medial septum/vertical diagonal band, dorsal subiculum, and dorsal lateral geniculate nucleus > the mammillary bodies and cingulate cortex > whole neocortex. In contrast to estimates of total neuron number, estimates of apoptotic cell number in Nissl-stained sections at 8 h after ethanol treatment provided a less reliable predictor of adult neuron loss. The findings show that ethanol-induced neonatal apoptosis often causes immediate neuron deficits that persist in adulthood, and furthermore suggests that the brain may have limited capacity to compensate for ethanol-induced neuron loss.
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Affiliation(s)
- John F. Smiley
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States
- Department of Psychiatry, School of Medicine, New York University, New York, NY, United States
- *Correspondence: John F. Smiley,
| | - Cynthia Bleiwas
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States
| | - Brandon M. Marino
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States
| | - Prerana Vaddi
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States
| | | | - Donald A. Wilson
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States
- Department of Child and Adolescent Psychiatry, School of Medicine, New York University, New York, NY, United States
- Department of Neuroscience and Physiology, School of Medicine, New York University, New York, NY, United States
| | - Mariko Saito
- Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States
- Department of Psychiatry, School of Medicine, New York University, New York, NY, United States
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Ehlting A, Zweyer M, Maes E, Schleehuber Y, Doshi H, Sabir H, Bernis ME. Impact of Hypoxia-Ischemia on Neurogenesis and Structural and Functional Outcomes in a Mild-Moderate Neonatal Hypoxia-Ischemia Brain Injury Model. Life (Basel) 2022; 12:life12081164. [PMID: 36013343 PMCID: PMC9410039 DOI: 10.3390/life12081164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 07/23/2022] [Accepted: 07/26/2022] [Indexed: 11/16/2022] Open
Abstract
Hypoxic-ischemic encephalopathy (HIE) is a common type of brain injury caused by a lack of oxygen and blood flow to the brain during the perinatal period. The incidence of HIE is approximately 2−3 cases per 1000 live births in high-income settings; while in low- and middle-income countries, the incidence is 3−10-fold higher. Therapeutic hypothermia (TH) is the current standard treatment for neonates affected by moderate−severe HIE. However, more than 50% of all infants with suspected HIE have mild encephalopathy, and these infants are not treated with TH because of their lower risk of adverse outcomes. Despite this, several analyses of pooled data provide increasing evidence that infants who initially have mild encephalopathy may present signs of more significant brain injury later in life. The purpose of this study was to expand our knowledge about the effect of mild−moderate hypoxia-ischemia (HI) at the cellular, structural, and functional levels. An established rat model of mild−moderate HI was used, where postnatal day (P) 7 rats were exposed to unilateral permanent occlusion of the left carotid artery and 90 min of 8% hypoxia, followed by TH or normothermia (NT) treatment. The extent of injury was assessed using histology (P14 and P42) and MRI (P11 and P32), as well as with short-term and long-term behavioral tests. Neurogenesis was assessed by BrdU staining. We showed that mild−moderate HI leads to a progressive loss of brain tissue, pathological changes in MRI scans, as well as an impairment of long-term motor function. At P14, the median area loss assessed by histology for HI animals was 20% (p < 0.05), corresponding to mild−moderate brain injury, increasing to 55% (p < 0.05) at P42. The data assessed by MRI corroborated our results. HI led to a decrease in neurogenesis, especially in the hippocampus and the lateral ventricle at early time points, with a delayed partial recovery. TH was not neuroprotective at early time points following mild−moderate HI, but prevented the increase in brain damage over time. Additionally, rats treated with TH showed better long-term motor function. Altogether, our results bring more light to the understanding of pathophysiology following mild-moderate HI. We showed that, in the context of mild-moderate HI, TH failed to be significantly neuroprotective. However, animals treated with TH showed a significant improvement in motor, but not cognitive long-term function. These results are in line with what is observed in some cases where neonates with mild HIE are at risk of neurodevelopmental deficits in infancy or childhood. Whether TH should be used as a preventive treatment to reduce adverse outcomes in mild-HIE remains of active interest, and more research has to be carried out in order to address this question.
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Affiliation(s)
- Anne Ehlting
- Department of Neonatology and Pediatric Intensive Care, Children’s Hospital, University of Bonn, 53127 Bonn, Germany; (A.E.); (M.Z.); (E.M.); (Y.S.); (M.E.B.)
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), 53127 Bonn, Germany;
| | - Margit Zweyer
- Department of Neonatology and Pediatric Intensive Care, Children’s Hospital, University of Bonn, 53127 Bonn, Germany; (A.E.); (M.Z.); (E.M.); (Y.S.); (M.E.B.)
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), 53127 Bonn, Germany;
| | - Elke Maes
- Department of Neonatology and Pediatric Intensive Care, Children’s Hospital, University of Bonn, 53127 Bonn, Germany; (A.E.); (M.Z.); (E.M.); (Y.S.); (M.E.B.)
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), 53127 Bonn, Germany;
| | - Yvonne Schleehuber
- Department of Neonatology and Pediatric Intensive Care, Children’s Hospital, University of Bonn, 53127 Bonn, Germany; (A.E.); (M.Z.); (E.M.); (Y.S.); (M.E.B.)
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), 53127 Bonn, Germany;
| | - Hardik Doshi
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), 53127 Bonn, Germany;
| | - Hemmen Sabir
- Department of Neonatology and Pediatric Intensive Care, Children’s Hospital, University of Bonn, 53127 Bonn, Germany; (A.E.); (M.Z.); (E.M.); (Y.S.); (M.E.B.)
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), 53127 Bonn, Germany;
- Correspondence:
| | - Maria Eugenia Bernis
- Department of Neonatology and Pediatric Intensive Care, Children’s Hospital, University of Bonn, 53127 Bonn, Germany; (A.E.); (M.Z.); (E.M.); (Y.S.); (M.E.B.)
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), 53127 Bonn, Germany;
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Chen A, Chen X, Deng J, Zheng X. Research advances in the role of endogenous neurogenesis on neonatal hypoxic-ischemic brain damage. Front Pediatr 2022; 10:986452. [PMID: 36299701 PMCID: PMC9589272 DOI: 10.3389/fped.2022.986452] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Hypoxic-ischemic brain damage (HIBD) is the main cause of perinatal mortality and neurologic complications in neonates, but it remains difficult to cure due to scarce treatments and complex molecular mechanisms remaining incompletely explained. Recent, mounting evidence shows that endogenous neurogenesis can improve neonatal neurological dysfunction post-HIBD. However, the capacity for spontaneous endogenous neurogenesis is limited and insufficient for replacing neurons lost to brain damage. Therefore, it is of great clinical value and social significance to seek therapeutic techniques that promote endogenous neurogenesis, to reduce neonatal neurological dysfunction from HIBD. This review summarizes the known neuroprotective effects of, and treatments targeting, endogenous neurogenesis following neonatal HIBD, to provide available targets and directions and a theoretical basis for the treatment of neonatal neurological dysfunction from HIBD.
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Affiliation(s)
- Andi Chen
- Department of Anesthesiology, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Xiaohui Chen
- Department of Anesthesiology, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Jianhui Deng
- Department of Anesthesiology, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Xiaochun Zheng
- Department of Anesthesiology, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China.,Fujian Emergency Medical Center, Fujian Provincial Key Laboratory of Emergency Medicine, Fujian Provincial Key Laboratory of Critical Care Medicine, Fujian Provincial Co-Constructed Laboratory of "Belt and Road", Fuzhou, China
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