Duration of isoflurane-based surgical anesthesia determines severity of brain injury and neurological deficits after a transient focal ischemia in young adult rats

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Abstract

Tremendous efforts and funds invested in discovery of novel drug treatments for ischemic stroke have so far failed to deliver clinically efficacious therapies. The reasons for these failures are not fully understood. An indiscriminate use of isoflurane-based surgical anesthesia with or without nitrous oxide may act as an unconstrained, untraceable source of data variability, potentially causing false-positive or false-negative results. To test this hypothesis, a common transient suture middle cerebral artery occlusion (tMCAO) model of ischemic stroke in young adult male rats was used to determine the impact of a typical range of anesthesia durations required for this model on data variability (i.e., infarct volume and neurological deficits). The animals were maintained on spontaneous ventilation. The study results indicated that: (1) Variable duration of isoflurane anesthesia prior, during and after tMCAO is a significant source of data variability as evidenced by measurements of infarct volume and neurological deficits; and (2) Severity of brain injury and neurological deficits after tMCAO is inversely related to the duration of isoflurane anesthesia: e.g., in our study, a 90 min isoflurane anesthesia nearly completely protected brain tissues from tMCAO-induced injury and thus, would be expected to obscure the effects of stroke treatments in pre-clinical trials. To elevate transparency, rigor and reproducibility of stroke research and minimize undesirable effects of isoflurane on the outcome of novel drug testing, we propose to monitor, minimize and standardize isoflurane anesthesia in experimental surgeries and make anesthesia duration a required reportable parameter in pre-clinical studies. Specifically, we propose to adopt 20–30 min as an optimal anesthesia duration that both minimizes neuroprotective effects of isoflurane and permits a successful completion of surgical procedures in a suture tMCAO model of ischemic stroke in rodents. As the mechanisms and neuroprotective, metabolic and immune effects of general anesthesia are not fully understood, the results of this study cannot be blindly generalized to other anesthetics, animal species and experimental models.

Original languageEnglish
Pages (from-to)168-176
Number of pages9
JournalBrain Research Bulletin
Volume134
DOIs
StatePublished - 1 Sep 2017

Fingerprint

Isoflurane
Brain Injuries
Young Adult
Ischemia
Anesthesia
Middle Cerebral Artery Infarction
Sutures
Stroke
Information Storage and Retrieval
Nitrous Oxide
Neuroprotective Agents
Financial Management
Drug Discovery
General Anesthesia
Ventilation
Anesthetics
Rodentia
Therapeutics
Animal Models
Clinical Trials

Keywords

  • Anesthesia
  • Ischemic
  • Isoflurane
  • MCAO
  • Middle cerebral artery occlusion
  • Stroke

Cite this

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title = "Duration of isoflurane-based surgical anesthesia determines severity of brain injury and neurological deficits after a transient focal ischemia in young adult rats",
abstract = "Tremendous efforts and funds invested in discovery of novel drug treatments for ischemic stroke have so far failed to deliver clinically efficacious therapies. The reasons for these failures are not fully understood. An indiscriminate use of isoflurane-based surgical anesthesia with or without nitrous oxide may act as an unconstrained, untraceable source of data variability, potentially causing false-positive or false-negative results. To test this hypothesis, a common transient suture middle cerebral artery occlusion (tMCAO) model of ischemic stroke in young adult male rats was used to determine the impact of a typical range of anesthesia durations required for this model on data variability (i.e., infarct volume and neurological deficits). The animals were maintained on spontaneous ventilation. The study results indicated that: (1) Variable duration of isoflurane anesthesia prior, during and after tMCAO is a significant source of data variability as evidenced by measurements of infarct volume and neurological deficits; and (2) Severity of brain injury and neurological deficits after tMCAO is inversely related to the duration of isoflurane anesthesia: e.g., in our study, a 90 min isoflurane anesthesia nearly completely protected brain tissues from tMCAO-induced injury and thus, would be expected to obscure the effects of stroke treatments in pre-clinical trials. To elevate transparency, rigor and reproducibility of stroke research and minimize undesirable effects of isoflurane on the outcome of novel drug testing, we propose to monitor, minimize and standardize isoflurane anesthesia in experimental surgeries and make anesthesia duration a required reportable parameter in pre-clinical studies. Specifically, we propose to adopt 20–30 min as an optimal anesthesia duration that both minimizes neuroprotective effects of isoflurane and permits a successful completion of surgical procedures in a suture tMCAO model of ischemic stroke in rodents. As the mechanisms and neuroprotective, metabolic and immune effects of general anesthesia are not fully understood, the results of this study cannot be blindly generalized to other anesthetics, animal species and experimental models.",
keywords = "Anesthesia, Ischemic, Isoflurane, MCAO, Middle cerebral artery occlusion, Stroke",
author = "Nikhil Gaidhani and Fen Sun and Derek Schreihofer and Uteshev-Gaard, {Victor V.}",
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AU - Gaidhani, Nikhil

AU - Sun, Fen

AU - Schreihofer, Derek

AU - Uteshev-Gaard, Victor V.

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N2 - Tremendous efforts and funds invested in discovery of novel drug treatments for ischemic stroke have so far failed to deliver clinically efficacious therapies. The reasons for these failures are not fully understood. An indiscriminate use of isoflurane-based surgical anesthesia with or without nitrous oxide may act as an unconstrained, untraceable source of data variability, potentially causing false-positive or false-negative results. To test this hypothesis, a common transient suture middle cerebral artery occlusion (tMCAO) model of ischemic stroke in young adult male rats was used to determine the impact of a typical range of anesthesia durations required for this model on data variability (i.e., infarct volume and neurological deficits). The animals were maintained on spontaneous ventilation. The study results indicated that: (1) Variable duration of isoflurane anesthesia prior, during and after tMCAO is a significant source of data variability as evidenced by measurements of infarct volume and neurological deficits; and (2) Severity of brain injury and neurological deficits after tMCAO is inversely related to the duration of isoflurane anesthesia: e.g., in our study, a 90 min isoflurane anesthesia nearly completely protected brain tissues from tMCAO-induced injury and thus, would be expected to obscure the effects of stroke treatments in pre-clinical trials. To elevate transparency, rigor and reproducibility of stroke research and minimize undesirable effects of isoflurane on the outcome of novel drug testing, we propose to monitor, minimize and standardize isoflurane anesthesia in experimental surgeries and make anesthesia duration a required reportable parameter in pre-clinical studies. Specifically, we propose to adopt 20–30 min as an optimal anesthesia duration that both minimizes neuroprotective effects of isoflurane and permits a successful completion of surgical procedures in a suture tMCAO model of ischemic stroke in rodents. As the mechanisms and neuroprotective, metabolic and immune effects of general anesthesia are not fully understood, the results of this study cannot be blindly generalized to other anesthetics, animal species and experimental models.

AB - Tremendous efforts and funds invested in discovery of novel drug treatments for ischemic stroke have so far failed to deliver clinically efficacious therapies. The reasons for these failures are not fully understood. An indiscriminate use of isoflurane-based surgical anesthesia with or without nitrous oxide may act as an unconstrained, untraceable source of data variability, potentially causing false-positive or false-negative results. To test this hypothesis, a common transient suture middle cerebral artery occlusion (tMCAO) model of ischemic stroke in young adult male rats was used to determine the impact of a typical range of anesthesia durations required for this model on data variability (i.e., infarct volume and neurological deficits). The animals were maintained on spontaneous ventilation. The study results indicated that: (1) Variable duration of isoflurane anesthesia prior, during and after tMCAO is a significant source of data variability as evidenced by measurements of infarct volume and neurological deficits; and (2) Severity of brain injury and neurological deficits after tMCAO is inversely related to the duration of isoflurane anesthesia: e.g., in our study, a 90 min isoflurane anesthesia nearly completely protected brain tissues from tMCAO-induced injury and thus, would be expected to obscure the effects of stroke treatments in pre-clinical trials. To elevate transparency, rigor and reproducibility of stroke research and minimize undesirable effects of isoflurane on the outcome of novel drug testing, we propose to monitor, minimize and standardize isoflurane anesthesia in experimental surgeries and make anesthesia duration a required reportable parameter in pre-clinical studies. Specifically, we propose to adopt 20–30 min as an optimal anesthesia duration that both minimizes neuroprotective effects of isoflurane and permits a successful completion of surgical procedures in a suture tMCAO model of ischemic stroke in rodents. As the mechanisms and neuroprotective, metabolic and immune effects of general anesthesia are not fully understood, the results of this study cannot be blindly generalized to other anesthetics, animal species and experimental models.

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KW - Middle cerebral artery occlusion

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