This presentation discusses various animal models used to study stroke. It begins with background on stroke, noting that most strokes are ischemic and affect the middle cerebral artery. It then reviews several common animal models, including electrocoagulation, chemically induced, intraluminal filament, embolic, and photochemically induced models in rats and other species. The advantages and disadvantages of each model are discussed. Evaluation methods like infarct volume analysis and cylinder tests are also mentioned. Finally, the presentation calls for continued research to better mimic human post-stroke events in animal models.

1. Presentation Title
Your company information
Presented by:
Ms. Sneha Durugkar
Reg no.PC/2017-X/170
M.S. Pharmacology & Toxicology
NIPER, Guwahati 107/18/18

2. Contents
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3. Introduction
• Stroke is sudden death of brain cells.
• Approx. 87% of stroke are ischaemic,
in which MCA is affected.
• Most of the risk factors are like HTN,
high cholesterol, smoking.
• Only one FDA approved drug
available is rtpa .
• Most of the drugs get failure
in clinical trial due to
Heterogeneity in human .
• Animal models used in stroke are
either Transient Or Permanent .
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Fig. diagrammatic
representation of stroke

4. Middle
cerebral
artery
ICA
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Fig. Schematic representation of
blood supply by the MCA

5. Pathophysiology
Vessel occlusion
Cerebral blood flow
widespread cellular depolarization of
Na+
, k+
, ca2+
release of neurotransmitters ( glutamate)
Glutamate receptor activation & accumulation of ca
Lipid peroxidation , FR
generation , proteolytic enzyme
activation
Irreversible
neuronal
damage
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6. ischemia
Energy
production
Energy
production
Failure
of ionic
pumps
Cellular Na, ca , cl
Leucocyte
activation
mediators of
inflammation
Excitotoxin
release
Excitotoxin
release
Stimulation of
phospholipase
FFA
Arachidonic acid
endoperoxidaseendoperoxidase
PG , Leukotrienes
Cell
membrane
injury
Neuronal
death
Protease,NOS,
NO,ONOO
Cytoskeleton &
DNA breakdown,
PARP activation
Cytoskeleton &
DNA breakdown,
PARP activation
Mitochondrial
injury
Mitochondrial
injury
Oxygen
radical
generation
Oxygen
radical
generation
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7. Screening models
In viv0 In vitro
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8. Selection of model
 It depends upon class of drug & its MOA
 Examples:
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9. Electrocoagulation method
• Purpose: to study the oedema & brain swelling & correlate it with
infract size & increased brain volume associated with large MCA stroke.
• Species: Large Animals Like Cat, Miniature Pig, & Baboon.
• Method:
Surgery
(5%
Isoflurane)
Surgery
(5%
Isoflurane)
Electric current( 7W) passed
through tips of fine
diathermy forceps
Electric current( 7W) passed
through tips of fine
diathermy forceps
Cutting of
occluded
portion
Cutting of
occluded
portion
Crystal violet
staining & analyze
Crystal violet
staining & analyze
Ischemic area = cortex area of contralateral side - non
ischemic cortex of ipsilateral side
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5-6 min

10. Cont…
• Advantages: 1) Good reproducibility & low mortality.
2) Permanent ischemia . , visual confirmation.
3) Ability to produce infarct of different size at
different location.
• Disadvantages: 1) Not suitable for thrombolytic drugs
2) Requires cranioctomy.
• Advancement : By Using Devices Like Clips, Hooks ,
Inflatable Cuffs ( Larger Species)
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11. Chemically Induced Model
Principle: vasoconstriction is induced by either topical or intracerebral inj
of endothelin -1 .
Species : rat or mice ( sprague dawley male rat , 8 weeks old , 250-
300gm)
Method:
Anaesthesized with isoflurane(4%)
rats are housed under a 12:12 light/dark cycle
Surgery is done
3 l of 80 M(PBS) ET1 is infused at a rate ofμ μ
1 l per min.μ
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12. Cont……
• Advantages: 1) dose dependent ischemia can
be achieved.
2) visual confirmation .
• Disadvantages : 1) stability & potency issues .
Suture closed
Haematoxylin staining done
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Fig. MCA exposure Fig. Neck suture
Fig. staining

13. Intraluminal MCAOIntraluminal MCAO
• Principle : this technique involves occlusion of the CCA , by
introducing a suture directly into ICA & advancing the suture until it
interrupts the blood supply to MCA .
• Method :
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Limb paralysis

14. Cont...
Advantages : 1) no cranioctomy is required.
2) induce both permenant & transient ischemia.
Disadvantages: 1) reproducibility is less.
2) not suitable for thrombolytic drugs.
3) MCAO cannot be confirmed visually.
0
Advancement : laser doppler flowmetry probes are used.
Note: filament diameter should be matched to defines body wt. range of
rodent.
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15. 1507/18/18
Güzel A, Rölz R, Nikkhah G, Kahlert UD, Maciaczyk J. A microsurgical procedure for middle cerebral artery occlusion by intraluminal monofilament insertion
technique in the rat: a special emphasis on the methodology. Experimental & translational stroke medicine. 2014 Dec;6(1):6
Cont...

16. Embolic MCA occlusion
Species : rat, mice, rabbit, cat
Procedure:
Advantages: 1) clinical relevance.
2) occlusion in both cortical & subcortical structure.
Disadvantages: rapid progression so early cytotoxic & vasogenic edema
occurs
Blood drawn from animal to form autologus clots of
specific size .
Introduced into cerebral circulation via cannula inserted
Clot breakdown & reperfusion induced by thrombolytics ( eg rtpa)
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17. Photo chemically Induced Embolism
• Principle: this method induces a corticle infarct by systemic inj of
photoactive dye in combination with irradiation by light beam transmitted
through the intact skull .
• Species : sprague dawely male rat , 200-250gm
• Method :
SurgerySurgery
systemic inj.4 l of 20mg/ kg roseū
bengal + light wavelength 520nm for
20 min
systemic inj.4 l of 20mg/ kg roseū
bengal + light wavelength 520nm for
20 min
MRI
scanning
MRI
scanning
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18. Cont…
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19. Thrombin induced model
• Principle : Microinj. of thrombin induces clot & analyzed for CBF
volume & locomotor activity.
• Species: male swiss mice (25-30gm)
• Method :
After 20 min
19
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Surgical exposing
of MCA
Surgical exposing
of MCA
200 Lū tpa (10 mg /kg)
( tail vein)
200 Lū tpa (10 mg /kg)
( tail vein)
Laser doppler
flowmetry analysis
Laser doppler
flowmetry analysis
Animal
anaesthesized
isoflurane (5%)
Animal
anaesthesized
isoflurane (5%)
1 L alpha thrombin i.vū1 L alpha thrombin i.vū

20. Evaluation test
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Cylinder testCylinder test Infarct volume analysisInfarct volume analysis

21. In vitro model
• Principle: The in vitro release of adenosine, inosine, and hypoxanthine
from rat hippocampal slices can be determined with and without drug.
• Species : sprague dawley rat (150-200gm)
• Procedure: brain is decapitated & 400 ūm thick slices
Oxygen &
glucose
supply
No oxygen
& glucose
1-2 hrs 1-2 hrs
Adv: neuroprotective studies
Disadv: ischemic studies not
possible
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22. Summary
• Stroke is found as 3rd
most leading cause of death , as attack & sudden
death most commonly occurs.
• As aging is also a one of the cause , the neuronal damage cant be
recovered.
• Rtpa & surgical removal of clot are only the treatments for treating
stroke.
• Most of causes are unknown ,so most of the models are getting failure to
mimic the human stroke condition.
• Now a days SHR strains are used to correlate hypertension induced
stroke as well as HLA DR2 transgenic mice model for thrombolytic
studies are used .
• Still research is going on for mimicing the poststroke events which
commonly observed in human cases.
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23. References
• Yang S, Liu K, Ding H, Gao H, Zheng X, Ding Z, Xu K, Li P.
Longitudinal in vivo intrinsic optical imaging of cortical blood perfusion
and tissue damage in focal photothrombosis stroke model. Journal of
Cerebral Blood Flow & Metabolism. 2018 Jan 1:0271678X18762636
• Sommer CJ. Ischemic stroke: experimental models and reality. Acta
neuropathologica. 2017 Feb 1;133(2):245-61
• Khodanovich MY, Kisel AA. Animal models of cerebral ischemia. InAIP
Conference Proceedings 2015 Nov 17 (Vol. 1688, No. 1, p. 030037). AIP
Publishing.
• Güzel A, Rölz R, Nikkhah G, Kahlert UD, Maciaczyk J. A microsurgical
procedure for middle cerebral artery occlusion by intraluminal
monofilament insertion technique in the rat: a special emphasis on the
methodology. Experimental & translational stroke medicine. 2014
Dec;6(1):6.
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24. Thank you 2407/18/18