BIOMETHODOLOGY OF THE
MOUSE
Office of Laboratory Animal Care
University of Tennessee, Knoxville
General Behavior





Nocturnal
Non-aggressive towards
humans
Social
Barbering is common
Males are more likely to
fight if housed with nonlittermates
Weight Gain Chart
C57BL/6
Reproduction







Estrus Cycle 4–5 d
Gestation 19-21 d
Litter Size 10-12 pups
Eyes open 14 d
Weaning 21 d
Postpartum estrus
Reproductive life ~8 mo
Sexing



Newborns have a subtle difference
in anogenital distance
At 9 days of age, nipples are evident
in the female and absent in the
male
Adults have a marked difference in
anogenital distance
Housing

Adequate housing should provide the
following:



Clean, dry and safe area with adequate
ventilation, food and water
Visualization by personnel
Sufficient space to turn around and make
normal postural movements
Enclosure Recommendations

Primary enclosure space recommendations per the
Guide for the Care and Use of Laboratory Animals
Mice

Weight
(g)
Floor Area
(in2)
Height
(in)
<10
6
5
Up to 15
8
5
Up to 25
12
5
>25
≥15
5
UTK Mouse Cage Density Policy
http://www.vet.utk.edu/olac/pdf/Mouse_Cage_Density_Policy.pdf
Primary Enclosure

Microisolator top


Reduces spread of
pathogens
Wire-bar lid


Water bottle
Feed

Cage Bottom



Easy visualization
Solid bottom flooring
Bedding and
enrichment
Environmental Conditions
Room Recommendations




Temperature 68 – 79⁰F
Humidity 30 -70%
Ventilation 10 -15 air changes/hr.
Noise ≥85 db can cause



Stress
Metabolic changes
Reduced fertility
Identification
Ear Tags
Ear Punches
Identification

Cage Card
Procedures


Institutional Animal Care and Use Committee
(IACUC) protocol describes all procedures
that can be performed
A procedure is defined as any activity carried
out on a mouse such as:



Behavioral observation
Venipuncture
Surgery
Manual Restraint




Lift mouse by the base of
the tail and place on wire
bar lid
Push the mouse against the
wire bar to prevent escape
and advance the hand
toward the head.
Grasp the scruff of the
neck
Tuck tail between finger
and palm
Manual Restraint
Click to Watch Video
Mechanical Restraint
Decapicone
Plastic Adjustable Restrainer
Blood Collection

Survival Procedures




Orbital sinus
Tail vein prick
Facial vein
Non-Survival Procedures



Cardiac puncture
Cranial vena cava puncture
Axillary cut down
Blood Collection

Blood Collection Guidelines

Single blood draw


Multiple blood draws


≤1.0 ml per 100 grams of body weight
Maximum of 1.5 ml per 100 grams of body weight
within a 2 week period
Note: Average mouse body weight is ~20 grams
but can be highly variable between stock/strain
Blood Collection

Orbital sinus






For collecting up to 0.2 ml of blood
Anesthetize mouse
Hold the head steady
Insert pipette in the medial canthus of the eye
Rotate the tube between thumb and finger
Keeping eyelids closed, apply direct pressure using gauze
for hemostasis
Blood Collection

Tail Nick






For collecting up to 0.2 ml
of blood
Warm tail to dilate blood
vessel
Use proper restraint
Prep with 70% alcohol
Use #11 scalpel blade or
needle to nick the lateral
tail vein
Apply direct pressure for
hemostasis
Blood Collection

Facial Vein






Hold the mouse securely
Locate the puncture site
slightly caudal to the freckle
Apply petroleum based
lubricant to the site
Use a lancet or 18 gauge
needle to puncture the skin
Collect blood
Apply direct pressure for
hemostasis
Blood Collection

Cardiac





For collecting up to 1.0 ml of blood
Anesthetize mouse
Insert ≤25 gauge needle under sternum at a 20⁰ angle
Aspirate slowly
Euthanize mouse
Blood Collection
Click to Watch Video
Tissue Collection

Tail Biopsy



Limited to a maximum
of 2 times
Maximum of 5 mm
Analgesia/Anesthesia
is required for mice 21
days of age and older
Compound Administration

25 to 27 gauge needle
Maximum Administration Volumes (in ml/kg)
IM
0.05-0.1
IP
10-80
IV
(bolus)
5
PO
SC
(gastric gavage)
10-50
2-40
Compound Administration

Subcutaneous (SC or SQ)





The sides of the mouse
serve as good site for SQ
injections
Insert needle underneath
skin
Aspirate negative pressure
Inject compound and watch
for SQ bleb
To reduce leakage from the
injection site, pause before
retracting the needle
Compound Administration
Click to Watch Video
Compound Administration

Intraperitoneal (IP)



Locate lower right
quadrant for injection site
Aspirate
If an unintended
subcutaneous bleb occurs,
reposition the needle
Compound Administration
Click to Watch Video
Compound Administration

Intravenous (IV)




Lateral tail vein
Proper restraint
Heat source to dilate vessel
Apply direct pressure after
injection
Compound Administration

Gastric Gavage (PO)





Use a bulb-tipped gastric
gavage needle
Measure length of needle
from mouth to last rib
DO NOT FORCE the needle
down the esophagus
Inject solution
Observe mouse for signs of
distress
Compound Administration
Click to Watch Video
Anesthesia


When planning any procedure involving
anesthesia and/or surgery, please consult one
of the laboratory animal veterinarians in the
Office of Laboratory Animal Care (OLAC) at
974-5634.
The veterinarian can provide guidance and
detailed information in selecting the most
appropriate anesthetic and analgesic protocol
for your mice and procedure.
Aseptic Technique

Surgical Prep






After induction of anesthesia, clip hair from the
surgical site
Prep skin with povidone iodine, chlorhexidine or
other appropriate skin antiseptic
Scrub in a circular pattern, beginning in the center
and spiraling outward
Follow povidone iodine scrub with a 70% alcohol prep
Repeat Twice
End procedure with a light coat of povidone iodine
solution (not scrub) to the surgical site
Aseptic Technique



Place a sterile drape
over the mouse
Anything that touches
the surgical site must
be sterile
Non-absorbable
sutures/clips should be
removed in 7-14 days
Surgical Monitoring




Prevent pain, hypoxia, and hypothermia
Monitor withdrawal reflex
Provide a source of external heat
Provide appropriate analgesics for postoperative pain management
Record of Medical Care
Record of Medical Care
Euthanasia

Inhalant Anesthetic Overdose



Carbon Dioxide






Isoflurane
End the procedure with a thoracotomy or cervical dislocation
Place mouse in the chamber
Turn on CO2 flow into the chamber
Once the mouse has stopped breathing, wait at least 1 minute
before removing the mouse from the chamber
End the procedure with a thoracotomy or cervical dislocation
Substantially prolonged in neonates
Cervical Dislocation


Performed on anesthetized mice
Must be performed by skilled personnel
Occupational Health and Safety

PPE (Personal Protective
Equipment)


Protects handler and mouse
May include: gloves, gowns, lab
coats, shoe covers, hair bonnets,
face masks
Prevention of Infectious Disease

Colony Health Surveillance


Sentinel mice detect for presence of infectious
pathogens and parasites in the research colony
Mouse Antibody Production Test (MAP Test) and
PCR


A test for cell lines and tumors for murine viruses
Included in every animal use protocol
Procurement of Mice


APPROVED vendors include Charles River, Jackson
Labs, Harlan, NCI-Frederick, and Taconic
 Mice that are shipped from a non-approved
vendor source must be approved by OLAC before
the mice are procured.
An animal requisition form must be submitted
to the facility manager:
http://www.vet.utk.edu/olac/pdf/animal_acquisition_form.pdf
Quarantine



Quarantine is required if receiving mice from
an unapproved vendor
The minimum quarantine period is six (6)
weeks
No experimental manipulations or breeding
can be initiated during the quarantine period
unless approval has been granted by an OLAC
veterinarian
Health Concerns

General appearance




Lethargy
Aggressiveness
Hunched posture
Coat



Piloerection
Hair loss
Unkempt appearance
Health Concerns
Abnormal masses
Skin lesions
Health Concerns

Teeth
Normal
Malocclusion
Body Condition Scoring
Ullman-Cullere, et al. 1999
Tumor Production

Four criteria for euthanasia:




Tumor size of 1.5 cm in
diameter or tumor ulceration
Body condition score of 1
Tumor interferes with
function of vital organs
Tumor significantly interferes
with locomotion
Reporting Signs of Pain or Distress

For Mice That Require Veterinary Care



Complete the red “Sick Animal”
cage card
Attach card to cage
Notify facility manager or

Print Clinical Case Request Form
http://www.vet.utk.edu/olac/pdf/CLINICAL_CASE_REQUEST.pdf


Fax form to the OLAC office 974-5649
Assessment of the mouse’s condition and
treatments will be recorded on the “Sick
Animal” card
10 Question Quiz
References





GUIDE FOR CARE AND USE OF LABORATORY ANIMALS. National
Academy Press, 2011.
Lawson, PT. 2005. ASSISTANT LABORATORY ANIMAL TECHNICIAN
(ALAT) TRAINING MANUAL. The American Association for
Laboratory Animal Science, Memphis, TN.
Suckow M, Danneman P, Brayton C. 2001. THE LABORATORY
MOUSE. CRC Press, Boca Raton, FL.
Ullman-Cullere, M.H. and Foltz, C.J. 1999. Body Condition
Scoring: A Rapid and Accurate Method for Assessing Health Status
in Mice. Lab Anim Sci 49(3) 319-323.
Presentation: Chris Carter, OLAC UTK