Biology Reference
In-Depth Information
The mean contusion volume at 2 weeks after injury was significantly
less in the Epo treated groups when compared with the saline
group, but this effect was dependent on the administration time.
The best improvement in outcome was obtained when the Epo
was administered within 6 h after injury.
4
Notes
1. It is important to check that the gas cylinders are full (O
2
, air)
and the vaporizer has adequate isoflurane. It is important to
check (before every set of experiments) that the tubings and
their connections are secure. It is prudent to connect the cut end
of a glove finger (to serve as a balloon) to the “Y” connector that
goes into the ET tube and turn on the ventilator to make sure
that it bellows with each cycle of respiration. The infant laryno-
scope blade can be cut along its sloping side and the tip so that
it will fit into the mouth of the rat. The cannula of the 14/16 G
angiocatheter is used as the ET tube in rats. The sharp tip of the
catheter is cut and made smooth (to avoid injury to the trachea).
The total length of the cannula is kept at 2.5-3 cm to avoid tra-
cheal perforation (if it is too long). An elastic tie (usually the
elastic band from face masks can be used) is tied across the hard
proximal part of the catheter. The ends can be later used to tie
the tube to the lower jaw of the rat, once it is intubated. The
position of the cannula is confirmed by giving manual compres-
sion and looking for expansion of the chest, by looking for sym-
metrical movement of the chest, looking for respiratory rate that
should corresponds with the rate set on the ventilator, and by
looking for progressive distention of abdomen as the stomach
will distend if the tube is wrongly placed into the esophagus.
2. It is important to make sure that the mouse is breathing during
the procedure. It is better to start the incision from 5 to 8 mm
below the mouth in the midline. Stay in the midline while dis-
secting the pre-tracheal muscles to avoid injury to neck vessels.
In mice that are old, the thyroid may be large and the fat may be
abundant. This can be usually dissected with a little bit of
patience. Slide the tip of cannula along the curve of the tongue
till there is a minimal resistance from structures of larynx (tip can
usually seen through muscles in the proximal part of the inci-
sion). Its tip is then lowered little bit (<1 mm) and advanced
into the trachea (this step is visualized through the translucent
tracheal wall). Do not use any force while maneuvering the tip
into the trachea as it may injure the trachea and cause subcuta-
neous emphysema. The proximal and outer most PE tube should
be long enough to allow its connection with the “Y” junction of
the tubing that come from the ventilator. This is helpful
especially when the animal is fixed in the stereotactic frame.
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