THE INSTITUTIONAL ANIMAL CARE AND USE COMMITTEE (IACUC)
IACUC STANDARD PROCEDURES
INDUCTION AND MONITORING OF EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS
(EAE) IN RODENTS
General: This standard procedure is designed to provide a single source of information for
investigators that use rodent models of experimental autoimmune encephalomyelitis (EAE) and
related demyelinating diseases. EAE is a demyelinating disease of the central nervous system (CNS)
that serves as a model of CNS autoimmune disease, most often human multiple sclerosis (MS).
Description of procedure: EAE can be induced by genetic manipulation or by administering
combinations of CNS components (cells and/or peptides) and Complete Freund’s Adjuvant (CFA),
often with pertussis toxin or viral/pathogen inoculation, or by administration of myelin-specific T cells in
the absence of CFA. These combinations result in a complex spectrum of acute, chronic and
relapsing-remitting disease courses that most often result in varying degrees of progressive
ascending paralysis. Due to the extreme variability in the onset and progression of clinical signs and
disease course, close monitoring and provision of supportive care are necessary for EAE animals.
ASSESSMENT
Many investigators already use scoring systems, but often with subtle differences. It is most important
to define levels of care to be provided by the clinical signs. If lab-specific scoring systems are used to
assess the animals, clearly defined clinical signs and management must be described in the IACUC
protocol and posted in the housing room. All EAE animals must be listed in Category E.
Common Clinical Signs of EAE
Sign
Tail Tone
Description
Decreased tail tone or a flaccid tail is often the first noticeable clinical sign
in progressive paralysis.
Hind Limb Paresis
Weakness in the hind limbs. Animal is unable to grasp with hind limbs or
is unable to right itself if turned on its side or back. Animals may have
difficulty moving or appear off balance.
Hind Limb Paraplegia
Inability to move one or both hind limbs.
Urinary Incontinence
Urine leaking. May be seen as wetness or skin irritation (dermatitis)
around prepuce or vulva. May predispose animals to urinary tract
infection (UTI).
Dehydration
Decreased skin turgor. When the skin at the scruff or nape of the
neck is gently pinched, it returns very slowly or stays tented.
Quadriparesis
Weakness of forelimbs in addition to hind limb dysfunction.
Distended Abdomen
Quadriplegia
Dyspnea
Moribund
A distended abdomen may indicate inability to urinate voluntarily, or
other conditions such as atonic bladder. Mice should be inspected to
determine whether manual expression may be necessary.
Animal develops inability to move hindlimbs and forelimbs. Paralysis of
all limbs.
Abnormal or difficulty breathing. May be rapid, slow and deep, or
erratic.
Animal is not moving. Often hunched or recumbent, dyspneic and
sometimes gasping.
SCORING SYSTEM
Body Condition Score (BCS) should always be used to assess the general physical
condition of the animals to effectively follow the progression of disease in the EAE rodent.
Clinical signs and ascending paralysis in EAE should be assessed on a scale of 0 – 5 (see
below), with “0” being clinically normal and “5” being paralysis of all limbs (quadriplegia).
0
1
2
3
4
5
6
-
Clinically normal
Decreased tail tone or weak tail only
Hind limb weakness (paraparesis)
Hind limb paralysis (paraplegia) and/or urinary incontinence
Weakness of forelimbs with paraparesis or paraplegia (quadriparesis)
Paralysis of all limbs (quadriplegia)
Moribund
ANIMAL CARE AND NOTIFICATION OF VETERINARY STAFF
1. At the time of inoculation with a substance intended to elicit an EAE model, each cage
should be labeled in some way to clearly indicate it is an “EAE Model”.
a. This must be communicated to LARC veterinary staff to ensure their
status and expected progression is known.
b. The “EAE Model” labeled cage card should include the inoculation
date and name of contact with day/night telephone numbers (if not
already listed as the contact on the cage card).
2. Score of 1-2: When initial clinical signs are noticed (e.g. flaccid tail or paresis), water
and food must be made more accessible.
a. If possible, long sipper tubes can be added to water bottles.
b. Gel products that provide water and/or nutrients should be placed on the cage floor
daily and recorded.
c. Semi-solid or liquid nutritional supplements may also be placed in the cage.
3. Score of 3: Animals must be individually identified by some means at this point
and an EAE card, indicating when the animal was last scored must be initiated
and kept in the room.
a. With the onset of hind limb paraplegia (hind limb paralysis), the animals should
be monitored for distended (enlarged) abdomen, which could indicate atonic
urinary bladder.
b. Animals must be monitored for lesions secondary to urinary incontinence such
as dermatitis, urine scald, penile prolapse and tail lesions. Alpha-dri bedding is
recommended as it provides a softer surface and may prevent or minimize
some secondary lesions.
c. Paraplegic animals must be evaluated at least 3 times weekly, along with being
monitored more frequently to increase the likelihood of noticing quadriplegic or
moribund animals as early as possible in the disease course.
d. Hydration should be evaluated visually or by checking skin turgor. If
dehydrated, 1 ml of sterile saline (or other approved fluid) should be given
subcutaneously or intraperitoneally.
4. Score of 4: When weakness in the front limbs is noted with hind limb paraplegia
(quadriparesis), then the mice are required to be evaluated at least once daily.
a. IACUC protocol must describe a time limit that animals will be kept on study at a
score of 4. Time limits greater than 24 hours must be scientifically justified.
5. Score of 5: If animals progress to quadriplegia, they must be euthanized by the end of
that day. Animals with BCS 2 or less, or 20% body weight loss from their baseline must
be euthanized.
6. Animals found in a moribund state must be euthanized immediately.
7. The assessment, care and documentation for EAE animals are the responsibility of the
Principal Investigator. These responsibilities are required 7 days a week, including
holidays. Records must be made available to the IACUC upon request.
8. Training in assessment, monitoring and supportive care is available through LARC
veterinary staff upon request.
RECORD KEEPING
1. All daily monitoring, assessments, scoring, weights, supportive care and treatment
must be recorded in a monitoring log maintained by the laboratory. Records must
be presented to LARC or IACUC personnel upon request.
2. Notations in the record must include name, date and time of entry, and
pertinent information.
EAE CLINICAL SIGNS AND CARE

Score
Clinical signs
Care to be provided
0
Clinically
normal
- Baseline weight or body score prior to induction
- Clearly mark “EAE Model” on each cage card
1
Weak tail
- Initiate EAE score card or sheet
- Keep record in a monitoring log in or near animal room
- Include name, date, and comment for each entry
2
Weak hind
limbs
- Provide additional water source (e.g. long sipper tubes,
gel product, etc.)
- Provide moistened food pellets on floor of cage
- Weigh animal weekly
3
Paralyzed hind
limbs;
+/- urinary
incontinence
- Monitor, weigh and score animals at least 3 times per week
- Monitor for skin lesions, urine scald, penile prolapse
- Monitor for dehydration; provide sterile SQ fluids
as needed.
- Recommended:
-
4
Weak front
limbs with
paralyzed hind
limbs
Change to soft bedding (Alpha-dri)
Separate affected mice from unaffected (0) mice to
prevent trampling.
- Monitor animal daily and record EAE score
- Continue all care described above
- If the animal develops an atonic urinary bladder,
express bladder twice daily. Contact LARC veterinary
staff for assistance as needed.
- Required:
-
Change to soft bedding (Alpha-dri).
Separate affected mice from mice with a score of
1 or zero to prevent trampling.
-
Adhere to time limit described in IACUC protocol
5
Paralyzed front
and hind limbs
-
Mice exhibiting these signs must be euthanized by the
end of the day.
Moribund
Recumbent;
+/- abnormal
breathing
-
These animals must be euthanized immediately.
Literature search words required:
Literature search was performed for refinement of this Standard Procedure in July 2014:
Key Words
Mouse EAE
NEW 9/2014
Search Sites
PubMed,
AGRICOLA
Years Covered
1970-2014