Premium
Slow‐ and fast‐twitch rat hind limb skeletal muscle phenotypes 8 months after spinal cord transection and olfactory ensheathing glia transplantation
Author(s) -
Negredo Pilar,
Rivero JoséLuis L.,
González Beatriz,
RamónCueto Almudena,
Manso Rafael
Publication year - 2008
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2007.149120
Subject(s) - skeletal muscle , biology , olfactory ensheathing glia , spinal cord , hindlimb , transplantation , spinal cord injury , anatomy , medicine , endocrinology , central nervous system , neuroscience , olfactory bulb
Paralysed skeletal muscle of rats with spinal cord injury (SCI) undergoes atrophy and a switch in gene expression pattern which leads to faster, more fatigable phenotypes. Olfactory ensheathing glia (OEG) transplants have been reported to promote axonal regeneration and to restore sensory‐motor function in animals with SCI. We hypothesized that OEG transplants could attenuate skeletal muscle phenotypic deterioration and that this effect could underlie the functional recovery observed in behavioural tests. A variety of morphological, metabolic and molecular markers were assessed in soleus (SOL) and extensor digitorum longus (EDL) muscles of spinal cord transected (SCT), OEG‐transplanted rats 8 months after the intervention and compared with non‐transplanted SCT rats and sham‐operated (without SCT) controls (C). A multivariate analysis encompassing all the parameters indicated that OEG‐transplanted rats displayed skeletal muscle phenotypes intermediate between non‐transplanted and sham‐operated controls, but different from both. A high correlation was observed between behaviourally tested sensory‐motor functional capacity and expression level of slow‐ and fast‐twitch hind limb skeletal muscle phenotypic markers, particularly the histochemical glycerol‐3‐phosphate dehydrogenase activity (−0.843, P < 0.0001) and the fraction of variant 2s of the slow regulatory myosin light chain isoform (0.848, P < 0.0001) in SOL. Despite the mean overall effect of OEG transplants in patterning skeletal muscle protein expression towards normal, in 6 out of 9 animals they appeared insufficient to overcome fibre type switching and to support a consistent and generalized long‐term maintenance of normal skeletal muscle characteristics. The interplay of OEG and exercise‐mediated neurotrophic actions is a plausible mechanism underlying OEG transplantation effects on paralysed skeletal muscle.