Article

Spinal cord injury (SCI) induces alterations in cardio-autonomic
control of which autonomic dysreflexia (AD), a condition characterized by
life-threatening hypertension, is arguably the most insidious. Passive hind-limb
cycling represents a low-cost therapeutic intervention with demonstrable
cardiovascular, sensory, and motor benefits. OBJECTIVE: To investigate the effect
of passive hind-limb cycling on AD in rodents with T3 SCI. METHODS: Forty-five
male Wistar rats were evenly assigned to either uninjured control (CON), SCI, or
SCI plus hind-limb cycling exercise (SCI-EX). At the end of the experimental
period (day 32), rats were randomly assigned to stream 1 (n = 24) or stream 2 (n
= 21). Stream 1 rats were assessed for AD severity (pressor response to
colorectal distension) and were then perfused for tissue dissection and
immunohistochemistry. Stream 2 rats underwent excision of the superior mesenteric
artery for in vitro myography assessments. RESULTS: From 2 weeks post-SCI
onwards, SCI-EX rats exhibited a significant reduction in the pressor response to
colorectal distension versus SCI (P< .001). Reduced AD severity in SCI-EX rats
was accompanied by a prevention of the SCI-induced increase in density of
CGRP(+)afferents in the dorsal horn (P= .001). Conversely, both SCI and SCI-EX
rats exhibited a similar degree of mesenteric endothelial dysfunction and
alpha-adrenoceptor hypersensitivity versus CON. CONCLUSION: Passive hind-limb
cycling reduces the severity of AD in SCI, and is correlated with changes in
primary afferent morphology, but has limited effects on the peripheral
vasculature.
CI - (c) The Author(s) 2015.

Langue : ANGLAIS