Effect of treadmill training on autonomic dysreflexia in spinal cord--injured rats.
BACKGROUND
Weight-supported treadmill training is an emerging rehabilitation method used to improve locomotor ability in patients with spinal cord injury (SCI). However, little research has been undertaken to test the effect of such training on other consequences of SCI, such as neuropathic pain and autonomic dysfunction.


OBJECTIVE
This study investigates the effects of chronic treadmill training on the development of autonomic dysreflexia (AD), a form of cardiovascular dysfunction common in patients with cervical or high thoracic injury.


METHODS
Treadmill training commenced in adult male rats (n = 11) 3 days following complete T4 transection, whereas a sedentary SCI group (n = 9) and an intact group (n = 6) had no intervention. Treadmill training (up to 0.4 m/s) lasted for 10 min/d 5 days a week, for 6 weeks. Weekly measurements of locomotor ability (BBB scale), baseline mean arterial pressure, and heart rate were made, as were cardiovascular responses to training and colorectal distension (to trigger AD).


RESULTS
Treadmill training improved BBB scores from 2 weeks post-transection onward (P = .010). However, it increased AD, resulting in augmented pressor responses from 2 to 6 weeks post-transection (P = .029). Comparison of the vascular response to phenylephrine under ganglionic blockade showed an enhanced vasoconstrictor response in the renal vasculature of trained SCI animals. Immunohistochemical comparison of the L1-L6 spinal cord segments showed an increased area of CGRP immunoreactivity in the dorsal horn (lamina III/IV) of treadmill-trained SCI compared with intact and sedentary SCI animals.


CONCLUSIONS
These results suggest that treadmill training exaggerated AD responses perhaps through a combination of enhanced vascular reactivity and central plasticity.
Laird
Angela S
AS
Department of Anatomy, School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia. angela.laird@med.kuleuven.be
Carrive
Pascal
P
Waite
Phil M E
PM
D000818:Animals; D020211:Autonomic Dysreflexia / Q000503:physiopathology / Q000534:rehabilitation*; D001794:Blood Pressure / Q000187:drug effects; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D002319:Cardiovascular System / Q000187:drug effects / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects; D008124:Locomotion; D008297:Male; D009043:Motor Activity; D010656:Phenylephrine / Q000494:pharmacology; D010805:Physical Conditioning, Animal / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D012720:Severity of Illness Index; D013116:Spinal Cord / Q000503:physiopathology; D013997:Time Factors; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D014662:Vasoconstrictor Agents; D010656:Phenylephrine; D015740:Calcitonin Gene-Related Peptide