Biology Reference
In-Depth Information
part of the total axonal population at the injury site of interest
(
11
). Although integrity of autonomic and sensory systems, par-
ticularly with regard to bowel and bladder function and pain (
12
)
are significant for a good recovery, much attention has widely
been directed to the assessment of locomotive performance. BBB
locomotor rating scale described by Basso, Beattie, and Bresnahan
(
13
) in 1995 is the most frequently used measure of motor perfor-
mance in rats. Animals scored (1-8) are able to move hindlimb
joint without weight support. Those scored (9-13) can make
varying degrees of hindlimb weight support and forelimb—
hindlimb coordination, while those score (14-22) demonstrated
improvements in paw and tail position, toe clearance, and trunk
stability during a fully supported and coordinated gait. Rather
than remaining with a BBB score of 0, rats with complete transec-
tions can achieve a score of 3 to 4, whereas mildly injured rats can
achieve the full score of 21 after a number of weeks (
8, 14
) (see
Notes 5 and 7). Its use allows the communication and standard-
ized comparison of results from different institutions. Moreover,
a modified version of the BBB scale has been developed for the
evaluation of mice after spinal cord injury. The grid walking test
(
15
), the narrow beam test (
16
), and the inclined plane test (
17
)
are other commonly used locomotor tests. During investigation
of cervical spinal cord injury, skilled forelimb movement can be
assessed by reaching tasks, in which the animal must grasp a small
food pellet placed at varying heights and deliver it to its mouth
(
18
). There also has been the development of sophisticated video
and computerized kinematic analysis systems for animals, which
may improve ability to detect small functional changes (
19
).
4
Notes
1. Models in which the spinal cord is sharply transected, either
completely or partially, are useful for studying the anatomic
regeneration of axons. They are complementary to the contu-
sion models, which better simulate the biomechanics and neu-
ropathology of human injury.
2.
Complete Transection
: The implication in studies using transec-
tion models is that with the ensured completeness of the lesion,
anterogradely labeled axons observed distal to the lesion have
indeed regenerated from above and are responsible for the
functional recover. The so-called “spinalized” animal can dem-
onstrate some native locomotor abilities of the completely
transected spinal cord after a period of gravity-assisted tread-
mill training of the hindlimbs (
20-22
) or pharmacologic inter-
vention such as intrathecally administered alpha adrenergic
agonists (
23, 24
). Apart from this type of injury, in case the
recovery is due to axonal regeneration of descending systems
Search WWH ::
Custom Search