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In This Article

  • Summary
  • Abstract
  • Introduction
  • Protocol
  • Representative Results
  • Discussion
  • Acknowledgements
  • Materials
  • References
  • Reprints and Permissions

Summary

Here we describe a protocol for the induction of murine traumatic brain injury via an open-head controlled cortical impact.

Abstract

The Centers for Disease Control and Injury Prevention estimate that almost 2 million people sustain a traumatic brain injury (TBI) every year in the United States. In fact, TBI is a contributing factor to over a third of all injury-related mortality. Nonetheless, the cellular and molecular mechanisms underlying the pathophysiology of TBI are poorly understood. Thus, preclinical models of TBI capable of replicating the injury mechanisms pertinent to TBI in human patients are a critical research need. The controlled cortical impact (CCI) model of TBI utilizes a mechanical device to directly impact the exposed cortex. While no model can full recapitulate the disparate injury patterns and heterogeneous nature of TBI in human patients, CCI is capable of inducing a wide range of clinically applicable TBI. Furthermore, CCI is easily standardized allowing investigators to compare results across experiments as well as across investigative groups. The following protocol is a detailed description of applying a severe CCI with a commercially available impacting device in a murine model of TBI.

Introduction

The Centers for Disease Control and Injury Prevention estimate that approximately 2 million Americans sustain a traumatic brain injury (TBI) every year1,2. In fact, TBI contributes to over 30% of all injury related deaths in the United States with healthcare costs nearing $80 billion annually and almost $4 million per person per year surviving a severe TBI3,4,5. The impact of TBI is highlighted by the significant long-term neurocognitive and neuropsychiatric complications suffered by its survivors with the insidious o....

Protocol

All procedures were approved by the Northwestern University Institutional Animal Care and Use Committee. C57BL/6 mice were purchased from the Jackson Laboratory and group housed at a barrier facility at the Center for Comparative Medicine at Northwestern University (Chicago, IL). All animals were housed in 12/12 h light/dark cycle with free access to food and water.

1. Induce anesthesia

  1. Anesthetize the mouse with ketamine (125 mg/kg) and xylazine (10 mg/kg) injected intraperitoneal.......

Representative Results

The impactor mounts directly on the stereotaxic frame allowing for as much as 10 µm resolution for control of the point of impact, depth and penetration. The electromagnetic forces employed can impart impact velocities ranging 1.5–6 m/s. This allows for unparalleled precision and reproducibility over the entire range of clinically relevant TBI. Investigators can run pilot experiments changing the injury parameters such as impactor tip size, impact velocity, and impact depth to determine the parameters that bes.......

Discussion

There are several steps that are critical for applying a reliable and consistent injury. First, the mouse must reach a deep plane of surgical anesthesia ensuring no movement during the performance of the craniectomy. While numerous anesthetic regimens may be used to induce general anesthesia in rodents, anesthetics that induce respiratory depression such as inhalational anesthetics may result in respiratory arrest when combined with a severe TBI. This protocol utilizes ketamine (125 mg/kg) and xylazine (10 mg/kg) injecte.......

Acknowledgements

This work was supported by National Institutes of Health Grant GM117341 and The American College of Surgeons C. James Carrico Research Fellowship to S.J.S.

....

Materials

NameCompanyCatalog NumberComments
AnaSed Injection Xylazine Sterile SolutionLLOYD, Inc.5939911020
Buprenorphine SR Lab 0.5mg/mLZoopharm-Wildlife Pharmaceuticals USABSRLAB0.5-182012
High Speed Rotary Micromotor KiT0Foredom Electric CompanyK.1070
Imapact one for Stereotaxix CCILeica Biosystems Nussloch GmbH39463920
Ketathesia Ketamine HCl Injection USPHenry Schein, Inc56344
Mouse Specific Stereotaxic BaseLeica Biosystems Nussloch GmbH39462980
Trephines for Micro DrillFine Science Tools, Inc18004-50

References

  1. Faul, M. . Traumatic Brain Injury in the United States: Emergency Department Visits, Hospitalizations and Deaths 2002-2006. , (2010).
  2. Roozenbeek, B., Maas, A. I., Menon, D. K. Changing patterns in the epidemiology of traumatic brain injury. Nature Reviews Neur....

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Murine ModelControlled Cortical ImpactTraumatic Brain InjuryStereotaxic FrameCraniectomyDura MaterImpactor TipBiomechanical ParametersReproducible Injury

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