MONITORING FOOD INTAKE IN MICE WITH THE HM-2 SYSTEM
Anne M.Wibskov, Dorte Thybring, Sidsel A. Larsen, Pernille Lyderik, Pernille Holm and Dorthe L.C. Almholt.
Pharmacology, Zealand Pharma A/S, Smedeland 26B, 2600 Glostrup, Denmark
Background
Material and Methods
The implementation and testing has involved
conditions of acclimatisation, chipping of the
animals, fixation of animals instead of mock
dosing, dosing with test compounds, washout
period and reuse of animals for several
compound dosing events to reduce the
number of animals needed.
3
Vehicle
Compound 1, 3 nmol/kg
Compound 1, 10 nmol/kg
Compound 2, 3 nmol/kg
Compound 2, 10 nmol/kg
Compound 2, 30 nmol/kg
2
1
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
4
3
2
Vehicle - day 1
Compound 1, 3 nmol/kg - day 1
Compound 1, 10 nmol/kg - day 1
Vehicle - day 2
Compound 1, 3 nmol/kg - day 2
Compound 1, 10 nmol/kg - day 2
1
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Time (h)
Time (h)
Accumulated food intake (1 h intervals)
for 24 hours after s.c. dosing with
compounds. (n=6-8)
Grey background indicates dark period.
Chip and chipping equipment
compared to the anesthetised mouse
Task
4
Accumulated Food Intake (g)
The HM-2 Feed Intake and Activity Monitor system is able to automatically measure and
record the undisturbed, real-time food and water intake and the feeding and activity
behaviour of multiple rodents housed in their home cage environment. We have
implemented and validated this system with the purpose of studying the effect of GLP-1
receptor agonists in C57BL/6 male mice.
Accumulated Food Intake (g)
Results
Challenge
Solution
Mice are anesthetised during
Chips are quite big and occasionally
chipping, and a single
Chipping the mice
fall out.
stitch is applied.
One week recovery.
Food and water is given in
Mice having difficulties finding their
the lid the first two days.
Acclimatisation
way into the feeding channels.
Shelter is provided already
Causing weight loss.
at arrival.
Number of mice in
Four mice in a cage, gives a
A steady hierarchy is hard to obtain.
cage
more steady group.
Struggles around and in the feeding
Changed animal supplier.
channels, mice pulling each other
Mice are ordered younger,
Mice biting each
out by the tail.
and are delivered in
other
Mice with tail bites and bald spots on
groups of four.
the hind part are observed.
Special produced food
Big pellets have a tendency to block
Choice of food
pellets acquired. Daily
the food container. If they’re too
type
observation of the
small they fall trough the fence.
containers.
What is the optimal number of
Eight animals divided in two
Size of dose
animals in a dose group,
cages is considered the
groups
considering reduction of animal
optimal size, considering
use, and statistic quality.
the risk of outliers.
Light cycle is set to 3 am – 3
pm, to enable dosing just
Increased activity/feeding is
before dark.
Light/ disturbance
observed on the curves at
Access to the room is
disturbances in the light period.
restricted, and every
entrance is noted.
Accumulated food intake (1 h intervals)
for 24 hours after s.c. dosing with
compounds (n=7-8) on two separate
dates, to show the reproducibility of the
system.
We have established a standard procedure for receiving, chipping and transfer of the
mice to the HM-2 system. The habituation time is approximately 7-9 days after transfer of
the mice to the HM-2 system, and a daily fixation of the mice make mock-dosing
unnecessary. Disturbances in the room of the HM-2 system are clearly observed on the
food intake. The majority of the food intake in the mice takes place in the dark period and
the effect of reference compounds, is clearly observed within the 12 h dark period that
follows dosing. We have shown excellent reproducibility of the reference compounds on
food intake, also while reusing the animals up to 3 times. The compound washout time is
approximately 4 days.
Conclusion
The HM-2 system is a precise way to
measure accurate food and water intake in
short term studies. We have successfully
established
a
protocol
for
testing
compounds with GLP-1 receptor mediated
inhibition of food and water intake, with a
minimum of stress and a reduction of
animals used in studies.
Mice installed in a HM-2 cage
TURNING PEPTIDES INTO DRUGS
Scand-LAS, May 25-28, 2011, Copenhagen, Denmark