Trigger 7: Animal models

Question 1

cervical dislocation occurs due to

Answer 1

injury

Question 2

types of injury that can be modelled

Answer 2

• penetrating/ focal injury - diffuse injury

Question 3

penetrating/ focal injury

Answer 3

Skull fracture- high impact blunt trauma

Foreign body (bullet, shrapnel)

Question 4

penetrating/ focal injury causes

Answer 4

focal lesion of cell necrosis, leukocyte infiltration and gliosis.

Question 5

Diffuse injury

Answer 5

Blunt head injury - Motor vehicle crash - Falls Blast injury - War-zone explosions

Question 6

diffuse injury causes

Answer 6

diffuse axonal injury and glial activation without focal cell death

Question 7

name 4 animal models

Answer 7

1) Controlled Cortical Impact Injury model (CCI) 2) Weight Drop Models 3) Fluid Percussion injury model (FPI) 4) Blast injury model

Question 8

Controlled Cortical Impact Injury model (CCI)

Answer 8

• Highly controlled focal impact to the brain at specific time, velocity and impact depth
• Carried out using an impactor targeted at the dura (outermost layer)
• Easily reproducible
• Mimics concussion, axonal injury and BBB dysfunction
• Minimal risk of rebound injury increases reliability of results obtained

Question 9

CCI procedure

Answer 9

♣ Craniotomy ♣ Impactor hits the dura ♣ Mouse then tested for cognitive and emotional defects

Question 10

Weight Drop Injury Models (2)

Answer 10

Marmarou’s weight drop model Shohami’s weight drop model

Question 11

Marmarou’s weight drop model

Answer 11

Procedure: o metal disk placed over the skull (preventing skull bone fractures) o weight dropped onto metal disk o Associated with diffuse injury

Question 12

Shohamil’s eight drop model

Answer 12

Procedure: o Weight is delivered to one side of the unprotected skull This model is mainly associated with focal (confined to one area of the brain) injury

Question 13

weigh drop models are useful for mimicking

Answer 13

contact sports, military activities and child abuse

Question 14

general weight drop model procedure

Answer 14

• Skull of mouse is exposed to guided free falling weight - Mass of weight and height determines how severe the injury.

Question 15

Fluid Percussion injury model (FPI) mimics

Answer 15

clinical TBI without skull fractures

Question 16

Fluid Percussion injury model (FPI) procedure

Answer 16

• Pressure pulse targeted at the intact dura via craniotomy which induces TBI - Pulse is generated when a pendulum strikes the piston of a reservoir of fluid - Fluid percussion injuries lead to brief brain tissue displacement and deformation

Question 17

benefits of fluid percussion model

Answer 17

• Highly reproducible, with fine-tuning of pendulum height - High mortality rates

Question 18

in FPI what is the main factor which determines severity of injury

Answer 18

Strength of the pressure pulse and site of the craniotomy

Question 19

blast injury model mimics

Answer 19

blast experienced by military personnel - TBI without external injuries

Question 20

the blast injury model investigates

Answer 20

how blast waves affect the brain by inducing mainly diffuse injuries

Question 21

what are commonly experienced after blast injury

Answer 21

• Chronic neuroinflammation and neurodegeneration commonly experienced

Question 22

negatives of blast model

Answer 22

• Effects of blasts are variable and tend to be different from TBIs induced mechanically at focal point

Question 23

in the blast model

Answer 23

the distance at which the mouse is placed along the shock tube greatly affects injury type and severity

Question 24

blast model is not

Answer 24

easily reproduced