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Zhao J, Xia C, Tang Y, Wan H. Role of PERK-mediated pathway in the effect of mild hypothermia after cerebral ischaemia/reperfusion. Eur J Clin Invest 2023; 53:e14040. [PMID: 37337313 DOI: 10.1111/eci.14040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 05/30/2023] [Accepted: 06/05/2023] [Indexed: 06/21/2023]
Abstract
BACKGROUND Hypothermia is an effective method of reducing brain injury caused by a variety of neurological insults. It is aimed to elucidate whether a change in the expression of PERK-mediated pathway proteins is an indicator of the neuroprotective effect of mild hypothermia after cerebral ischaemia/reperfusion. METHODS One hundred and ninety-two male C57BL/6 mice were randomly divided into three groups: a sham group, a cerebral normothermic ischaemia/reperfusion (I/R) group and a cerebral hypothermic I/R group. A cerebral ischaemia model was established by ligating the bilateral common carotid artery for 15 min. Mice in the hypothermia group stayed in a cage that was set at 33°C, sprayed with a spray of 70% ethanol, and blown with two high-speed fans. The state of neurons was assessed on micropreparations stained with haematoxylin-eosin and TUNEL. The expressions of GRP78, p-perk, p-eif2α, ATF4 and CHOP were measured by western blot analysis 6, 12, 24 and 72 h after reperfusion. RESULTS The number of surviving cells was significantly higher in the hypothermia group than in the group without hypothermia (p < .05). The GRP78 expression in the hypothermia group was statistically higher (p < .05) than in the ischaemia/reperfusion group. Optical densities of p-perk, p-eif2α and ATF4 in hippocampus CA1 neurons ischaemia were statistically significantly lower in the hypothermia group than in the ischaemia/reperfusion group (p < .05). The CHOP expression in the hypothermia group was statistically lower (p < .05) than in the ischaemia/reperfusion group. CONCLUSION Mild hypothermia for 6 h promoted moderate neuroprotection by mediating the expression of GRP78, p-PERK, p-eIF2α, ATF4 and CHOP.
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Affiliation(s)
- Jie Zhao
- Department of Anesthesiology, Zhejiang Hospital of Integrated Traditional Chinese and Western Medicine, Hangzhou, China
| | - Chenzhong Xia
- Department of Anesthesiology, School of Medicine, The Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Yingying Tang
- Department of Anesthesiology, School of Medicine, Women's Hospital, Zhejiang University, Hangzhou, China
| | - Haifang Wan
- Department of Anesthesiology, Zhejiang Hospital of Integrated Traditional Chinese and Western Medicine, Hangzhou, China
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Donadello K, Su F, Annoni F, Scolletta S, He X, Peluso L, Gottin L, Polati E, Creteur J, De Witte O, Vincent JL, De Backer D, Taccone FS. The Effects of Temperature Management on Brain Microcirculation, Oxygenation and Metabolism. Brain Sci 2022; 12:brainsci12101422. [PMID: 36291355 PMCID: PMC9599843 DOI: 10.3390/brainsci12101422] [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: 08/01/2022] [Revised: 09/26/2022] [Accepted: 10/20/2022] [Indexed: 11/16/2022] Open
Abstract
Purpose: Target temperature management (TTM) is often used in patients after cardiac arrest, but the effects of cooling on cerebral microcirculation, oxygenation and metabolism are poorly understood. We studied the time course of these variables in a healthy swine model.Methods: Fifteen invasively monitored, mechanically ventilated pigs were allocated to sham procedure (normothermia, NT; n = 5), cooling (hypothermia, HT, n = 5) or cooling with controlled oxygenation (HT-Oxy, n = 5). Cooling was induced by cold intravenous saline infusion, ice packs and nasal cooling to achieve a body temperature of 33–35 °C. After 6 h, animals were rewarmed to baseline temperature (within 5 h). The cerebral microvascular network was evaluated (at baseline and 2, 7 and 12 h thereafter) using sidestream dark-field (SDF) video-microscopy. Cerebral blood flow (laser Doppler MNP100XP, Oxyflow, Oxford Optronix, Oxford, UK), oxygenation (PbtO2, Licox catheter, Integra Lifesciences, USA) and lactate/pyruvate ratio (LPR) using brain microdialysis (CMA, Stockholm, Sweden) were measured hourly. Results: In HT animals, cerebral functional capillary density (FCD) and proportion of small-perfused vessels (PSPV) significantly decreased over time during the cooling phase; concomitantly, PbtO2 increased and LPR decreased. After rewarming, all microcirculatory variables returned to normal values, except LPR, which increased during the rewarming phase in the two groups subjected to HT when compared to the group maintained at normothermia. Conclusions: In healthy animals, TTM can be associated with alterations in cerebral microcirculation during cooling and altered metabolism at rewarming.
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Affiliation(s)
- Katia Donadello
- Department of Intensive Care, Erasme Hospital, Free University of Brussels, Route de Lennik 808, 1070 Brussels, Belgium
- Department of Anesthesia and Intensive Care B, Department of Surgery, Dentistry, Gynaecology and Paediatrics, University of Verona, AOUI-University Hospital Integrated Trust of Verona, Policlinico G.B. Rossi, Piazzale Ludovico Scuro, 37134 Verona, Italy
- Correspondence:
| | - Fuhong Su
- Department of Intensive Care, Erasme Hospital, Free University of Brussels, Route de Lennik 808, 1070 Brussels, Belgium
| | - Filippo Annoni
- Department of Intensive Care, Erasme Hospital, Free University of Brussels, Route de Lennik 808, 1070 Brussels, Belgium
| | - Sabino Scolletta
- Department of Intensive Care, Erasme Hospital, Free University of Brussels, Route de Lennik 808, 1070 Brussels, Belgium
- Service of Intensive and Critical Care Medicine, Department of Medical Science, Surgery and Neuroscience, University of Siena, 53100 Siena, Italy
| | - Xinrong He
- Department of Intensive Care, Erasme Hospital, Free University of Brussels, Route de Lennik 808, 1070 Brussels, Belgium
- Department of Intensive Care Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Lorenzo Peluso
- Department of Intensive Care, Erasme Hospital, Free University of Brussels, Route de Lennik 808, 1070 Brussels, Belgium
| | - Leonardo Gottin
- Departement of Cardio-Thoracic Anesthesia and Intensive Care, Department of Surgery, Dentistry, Gynaecology and Paediatrics, University of Verona, AOUI-University Hospital Integrated Trust of Verona, Piazzale Aristide Stefani, 37100 Verona, Italy
| | - Enrico Polati
- Department of Anesthesia and Intensive Care B, Department of Surgery, Dentistry, Gynaecology and Paediatrics, University of Verona, AOUI-University Hospital Integrated Trust of Verona, Policlinico G.B. Rossi, Piazzale Ludovico Scuro, 37134 Verona, Italy
| | - Jacques Creteur
- Department of Intensive Care, Erasme Hospital, Free University of Brussels, Route de Lennik 808, 1070 Brussels, Belgium
| | - Olivier De Witte
- Department of Neurosurgery, Erasme Hospital, Free University of Brussels, Route de Lennik 808, 1070 Brussels, Belgium
| | - Jean-Louis Vincent
- Department of Intensive Care, Erasme Hospital, Free University of Brussels, Route de Lennik 808, 1070 Brussels, Belgium
| | - Daniel De Backer
- Department of Intensive Care, Erasme Hospital, Free University of Brussels, Route de Lennik 808, 1070 Brussels, Belgium
- Department of Intensive Care, CHIREC, 1420 Braine L’Alleud, Belgium
| | - Fabio Silvio Taccone
- Department of Intensive Care, Erasme Hospital, Free University of Brussels, Route de Lennik 808, 1070 Brussels, Belgium
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Xu F, Wang Y, Gao H, Zhang X, Hu Y, Han T, Shen B, Zhang L, Wu Q. X-Ray Causes mRNA Transcripts Change to Enhance Orai2-Mediated Ca 2+ Influx in Rat Brain Microvascular Endothelial Cells. Front Mol Biosci 2021; 8:646730. [PMID: 34595206 PMCID: PMC8477418 DOI: 10.3389/fmolb.2021.646730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 03/05/2021] [Indexed: 12/13/2022] Open
Abstract
Background: Radiation-induced brain injury is a serious and treatment-limiting complication of brain radiation therapy. Although endothelial cell dysfunction plays a critical role in the development of this pathogenesis, the underlying molecular mechanisms remain elusive. Methods: Primary cultured rat brain microvascular endothelial cells (BMECs) were divided into five groups without or with exposure of x-rays delivered at 5 Gy or 20 Gy. For the irradiated groups, cells were continued to cultivate for 12 or 24 h after being irradiated. Then the mRNA libraries of each group were established and applied for next-generation sequencing. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were conducted to analyze the sequencing results. Quantitative polymerase chain reaction, western blotting, cck8 assay and intracellular calcium concentration assays were conducted to analyze the role of Orai2-associated SOCE in x-ray induced cellular injury. Results: In total, 3,005 transcripts in all the four x-ray-exposed groups of BMECs showed expression level changes compared with controls. With the dose of x-ray augment and the following cultured time extension, the numbers of differentially expressed genes (DEGs) increased significantly in BMECs. Venn diagrams identified 40 DEGs common to all four exposure groups. Functional pathway enrichment analyses indicated that those 40 DEGs were enriched in the calcium signaling pathway. Among those 40 DEGs, mRNA and protein expression levels of Orai2 were significantly upregulated for 24 h. Similarly, calcium influx via store-operated calcium entry, which is modulated by Orai2, was also significantly increased for 24 h in x-ray-exposed BMECs. Moreover, the change in SOCE was suppressed by btp-2, which is a non-selective inhibitor of Orai. Additionally, x-ray exposure induced a significant decrease of proliferation in BMECs in the dose- and time-dependent manner. Conclusion: These findings provide evidence for molecular mechanisms underlying BMECs dysfunction in development of radiation-induced brain injury and suggest new approaches for therapeutic targets.
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Affiliation(s)
- Fangfang Xu
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Yang Wang
- Department of Otolaryngology-Head and Neck Surgery, Lu'an People's Hospital, Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, China.,School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Huiwen Gao
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Xinchen Zhang
- Department of Radiotherapy, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yu Hu
- Department of Otolaryngology-Head and Neck Surgery, Lu'an People's Hospital, Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, China
| | - Tingting Han
- Department of Radiotherapy, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Bing Shen
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Lesha Zhang
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Qibing Wu
- Department of Radiotherapy, The First Affiliated Hospital of Anhui Medical University, Hefei, China
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The Role of Sphingomyelin Metabolism in the Protection of Rat Brain Microvascular Endothelial Cells by Mild Hypothermia. Neurocrit Care 2021; 36:546-559. [PMID: 34508278 DOI: 10.1007/s12028-021-01338-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 08/18/2021] [Indexed: 02/05/2023]
Abstract
BACKGROUND Sphingomyelin, composed of ceramide (CER), sphingosine (Sph), and sphingosine-1-phosphate (S1P), is an essential structural component of cellular membranes and plays an important role in the signal transduction regulating cell proliferation, differentiation, and apoptosis. CER is mainly metabolized to Sph, and under the action of sphingosine kinases (SphKs), Sph produces S1P, which can be converted back to Sph by S1P phosphatase. It is suggested that the fate of cells is controlled partly by the interconversion of CER and intracellular S1P. SphK2 is considered the main kinase of S1P synthesis in the central nervous system. The objective of this study was to explore the hypothesis that SphK2 and sphingomyelin metabolism participated in the process of cell apoptosis and the protection of mild hypothermia. METHODS Rat brain microvascular endothelial cells were divided into groups for intervention of SphK2 inhibitor, SphK2 small interfering RNA (SiRNA) transfection, ischemia-reperfusion, and mild hypothermia. After interventions, cell apoptosis was detected by 4,6-diamino-2-phenyl indole (DAPI) and flow cytometry, the expression of apoptosis-related protein was detected by Western Blot, and SphK2 enzyme activity and the content of sphingomyelin were determined. RESULTS ABC294640 and transfection of SphK2 SiRNA could increase apoptosis, accompanied by the increase of the expression of proapoptotic genes Caspase3 and Bax and the decrease of the expression of BCL-2. This effect could be partially reversed with mild hypothermia. Ischemia-reperfusion injury, transfection of SphK2 SiRNA, and the addition of ABC294640 could significantly inhibit the activity of SphK2, accompanied by the increase of CERs and the decrease of S1P. Mild hypothermia could reverse the changes of sphingolipids but have no significant effect on the activity of sphk2. CONCLUSIONS Mild hypothermia can inhibit the occurrence of apoptosis and reverse the changes of apoptosis-related genes and sphingomyelin content induced by ischemia-reperfusion injury, but the effect on sphk2 enzyme activity was not significant.
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Zhang T, Wang Y, Xia Q, Tu Z, Sun J, Jing Q, Chen P, Zhao X. Propofol Mediated Protection of the Brain From Ischemia/Reperfusion Injury Through the Regulation of Microglial Connexin 43. Front Cell Dev Biol 2021; 9:637233. [PMID: 34169070 PMCID: PMC8217990 DOI: 10.3389/fcell.2021.637233] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 04/09/2021] [Indexed: 11/13/2022] Open
Abstract
Cerebral ischemia/reperfusion (I/R) injury is a serious condition that leads to increased apoptosis of microglial and neurons in the brain. In this study, we identified that Cx43 expression level is significantly increased in the microglial cells during I/R injury. Using an in vitro model (hypoxia/reoxygenation-H/R injury), we observed that H/R injury leads to an increase in activation of microglial cells and increase in levels of pro-inflammatory markers such as IL-1β, IL-6, and TNF-α. Additionally, we could also observe significant increase in phosphorylation of Cx43 and Cav3.2 levels. To assess the role of H/R injured microglial cells on neuronal population, we cultured the neurons with conditioned media (MCS) from H/R injured microglial cells. Interestingly, we observed that microglial H/R injury significantly decreased Map2 expression and affected neuronal morphology. Further, we aimed to assess the effects of propofol on cerebral H/R injury, and observed that 40 μM propofol significantly decreased Cx43, Cx43 phosphorylation, and CaV3.2 levels. Additionally, propofol decreased apoptosis and increased Map2 expression levels in H/R injured neurons. Using silencing experiments, we confirmed that siCx43 could significantly improve the propofol's rescue after H/R injury in both microglia and neurons. We further developed an in vivo MCAO (middle cerebral artery occlusion) rat model to understand the effect of propofol in I/R injury. Interestingly, propofol treatment and downregulation of Cx43 significantly decreased the infract volume and apoptosis in these MCAO rats. Thus, this study clearly establishes that propofol protects the brain against I/R injury through the downregulation of Cx43 in microglial cells.
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Affiliation(s)
- Tingting Zhang
- Department of Anesthesiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yanyan Wang
- Department of Anesthesiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Qin Xia
- Department of Anesthesiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Zhiyi Tu
- Department of Anesthesiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jiajun Sun
- Department of Anesthesiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Qi Jing
- Department of Anesthesiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Pei Chen
- Department of Anesthesiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xuan Zhao
- Department of Anesthesiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
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Diao MY, Zheng J, Shan Y, Xi S, Zhu Y, Hu W, Lin Z. Hypothermia prevents hippocampal oxidative stress and apoptosis via the GSK-3β/Nrf2/HO-1 signaling pathway in a rat model of cardiac arrest-induced brain damage. Neurol Res 2020; 42:773-782. [PMID: 32529954 DOI: 10.1080/01616412.2020.1774210] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
OBJECTIVES The present study was undertaken to investigate the effects and related mechanisms of hypothermia on oxidative stress and apoptosis caused by cardiac arrest (CA)-induced brain damage in rats. METHODS The CA/CPR model was initiated by asphyxia. Body temperature in the normothermia and hypothermia groups was maintained at 37°C ± 0.2°C and 34°C ± 0.2°C, respectively, by surface cooling with an ice pack. First, neurological deficit scores (NDSs) were assessed, and then hippocampus samples were collected at 24 and 72 h after return of spontaneous circulation (ROSC). RESULTS The NDSs of rats were significantly reduced after CA, and hypothermia ameliorated neurological deficits. Varying degrees of changes in cellular nuclei and mitochondria were observed in the hippocampus following CA; however, morphological changes became less apparent after therapeutic hypothermia. Malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were higher in the hippocampus at 24 h after ROSC. In contrast, hypothermia did not alter MDA content, while SOD activity further increased. Furthermore, hypothermia reversed the caspase-3 enhancement observed in the normothermia group at 24 h after ROSC. CA also inhibited GSK-3β phosphorylation, promoted Nrf2 translocation to the nucleus, and downregulated HO-1 expression. However, hypothermia significantly reversed these CA-induced changes in GSK-3β phosphorylation, Nrf2 translocation, and HO-1 expression. CONCLUSION Hypothermia attenuated CA-induced neurological deficits and hippocampal morphology changes in rats. The protective effect of hypothermia following CA may have been related to inhibition of oxidative stress and apoptosis, and its underlying mechanisms may have been due, at least in part, to activation of the GSK-3β/Nrf2/HO-1 pathway.
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Affiliation(s)
- Meng-Yuan Diao
- Department of Critical Care Medicine, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, 261 Huansha Road , Hangzhou. 310006, People's Republic of China
| | - Jinhao Zheng
- Department of Critical Care Medicine, Changzheng Hospital, Naval Military Medical University , Shanghai, China
| | - Yi Shan
- Department of Critical Care Medicine, Changzheng Hospital, Naval Military Medical University , Shanghai, China
| | - Shaosong Xi
- Department of Critical Care Medicine, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, 261 Huansha Road , Hangzhou. 310006, People's Republic of China
| | - Ying Zhu
- Department of Critical Care Medicine, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, 261 Huansha Road , Hangzhou. 310006, People's Republic of China
| | - Wei Hu
- Department of Critical Care Medicine, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, 261 Huansha Road , Hangzhou. 310006, People's Republic of China
| | - Zhaofen Lin
- Department of Critical Care Medicine, Changzheng Hospital, Naval Military Medical University , Shanghai, China
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Yu H, Wang L, Zhang H, Wei W, Chen Y, Tang W, Wan Z. Effect of mild hypothermia on cerebral microcirculation in a murine cardiopulmonary resuscitation model. Microcirculation 2019; 26:e12537. [PMID: 30801897 DOI: 10.1111/micc.12537] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 02/10/2019] [Accepted: 02/20/2019] [Indexed: 02/05/2023]
Abstract
BACKGROUND We hypothesized that mild hypothermia may improve brain microcirculation by reducing cerebral microvascular endothelial cells apoptosis, and this effect may be maximized by moving up the initiation of mild hypothermia from after return of spontaneous circulation (ROSC) to the start of cardiopulmonary resuscitation (CPR). METHODS A total of 35 rats were randomized into the intra-arrest hypothermia group (IAH), post-resuscitation hypothermia group (PRH), normothermia group (NT), or the sham control group. A craniotomy exposed the parietal cortex for visualization of microcirculation. Ventricular fibrillation was electrically induced and untreated for 8 minutes, followed by 8 minutes of precordial compression and mechanical ventilation. Hypothermia (33 ± 0.5°C) in the IAH and PRH group was induced and maintained for 6 hours at the beginning of CPR or after ROSC, respectively. At baseline, 1, 3, and 6 hours, hemodynamic parameters were measured and the pial microcirculations were visualized with a sidestream dark field imaging video microscope. Microvascular flow index and perfused microvessel density (PMD) were calculated. Rats were euthanized, and brain tissues were removed at 3 and 6 hours separately. Expression of Bax, Bcl-2, and Caspase 3 in brain microvascular endothelial cells was examined by Western blot. RESULTS Microvascular flow index and PMD were significantly reduced after cardiac arrest and resuscitation (all P < 0.05), and the former was largely preserved by hypothermia regardless when the hypothermia treatment was induced (P < 0.05). Bax and Caspase 3 increased and Bcl-2 decreased significantly after resuscitation, and hypothermia treatment reversed the trend partly (all P < 0.05). A moderate correlation was observed between MFI and those proteins (Bcl-2/BAX: 3 hours: r = 0.730, P = 0.002; 6 hours: r = 0.743, P = 0.002). CONCLUSION Mild hypothermia improves cerebral microcirculatory blood supply, partly by inhibiting endothelial cell apoptosis. Mild hypothermia induced simultaneously with CPR has shown no additional benefit in microcirculation or endothelial cell apoptosis.
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Affiliation(s)
- Haifang Yu
- Department of Emergency Medicine, West China Hospital, Sichuan University, Chengdu, China.,Weil Institute of Emergency and Critical Care Medicine, Richmond, Virginia
| | - Lin Wang
- Department of Cardiology, Chengdu ShangjinNanfu Hospital, Chengdu, China
| | - Haihong Zhang
- Department of Emergency Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Wei Wei
- Department of Emergency Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Yao Chen
- Department of Emergency Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Wanchun Tang
- Weil Institute of Emergency and Critical Care Medicine, Richmond, Virginia
| | - Zhi Wan
- Department of Emergency Medicine, West China Hospital, Sichuan University, Chengdu, China
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