Biology Reference
In-Depth Information
3.4 End of the
Ventilation
Measurements
1. Via the software control, stop to register the acquired data.
2. Rapidly open the plethysmography chamber and take body
temperature with the rectal probe (this is the final body tem-
perature) (see Note 16).
3. Return the mouse in its original cage or anesthetize the animal
for euthanasy before harvesting tissues, depending on the
experimental protocol.
4. Turn off the gas cylinder(s) if applicable, the air supply pump,
the flowmeter, the thermometer, the humidity meter, and the
subsampling pump (see Note 23).
5. Be sure all the acquired data have been saved on the computer
for further analysis.
6. Turn off the acquisition system and the computer.
7. Carefully clean the plethysmography chamber (see Note 24).
3.5 Analyzing
Ventilation and
Metabolism Data
( See Note 25 )
For visual example purpose, typical results obtained by analysis of data
from whole-body unrestrained plethysmography before and after
hypoxia with mice injected or not with Epo are presented on Fig.
2
.
1. Respiratory frequency (fR) is directly evaluated as the number
of respiratory cycles per minute (resp. per min).
2. Tidal volume (
V
T
) is obtained with previously described calcu-
lations (
13
) based on an equation firstly described by Drorbaugh
and Fenn (
14
) in which
V
T
is expressed in ml per 100 g of body
weight (ml per 100 g) in BTPS (body temperature and pres-
sure, saturated) conditions.
3. Minute ventilation (
V
) is calculated as the product of fR and
V
T
and normalized to 100 g of body weight (ml/min/100 g).
4. O
2
consumption (
E
V
) is calculated as the difference between
the fractions of O
2
before and after the plethysmography cham-
ber corrected for STPD (standard temperature and pressure in
air-dry) conditions and normalized for body weight (ml
STPD
/
min/100 g).
5. CO
2
production (
O
2
V
) is calculated as the difference between
the fractions of CO
2
after and before the plethysmography
chamber corrected for STPD (standard temperature and pres-
sure in air-dry) conditions and normalized for body weight
(ml
STPD
/min/100 g).
CO
2
4
Notes
1. It is well possible to perform similar experiments with younger
mice, even from neonates, by using a specifically designed
insert in the plethysmography chamber. Such an insert increases
the relative impact of the small pressure fluctuations of the
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