The Effect of a Unilateral
Muscle Transplantation on the Muscle Fiber Type and the MyHC
Isoform Content in Unoperated Hind Limb Slow and Fast Muscles of
the Inbred Lewis Rats
G. ZACHAŘOVÁ, A. VADÁSZOVÁ, V. SMERDU1, G.
ASMUSSEN2, T. SOUKUP
Institute of Physiology, Czech Academy of Sciences, Prague,
Czech Republic, 1Institute of Anatomy, Medical Faculty,
Ljubljana, Slovenia, and 2Carl-Ludwig Institute for Physiology,
University of Leipzig, Leipzig, Germany
Received June 24, 2005
Accepted August 12, 2005
Summary
To reveal the effect of foreign innervation and altered thyroid
status on fiber type composition and the myosin heavy chain
(MyHC) isoform expression in the rat slow soleus (SOL) and fast
extensor digitorum longus (EDL) muscles, a method of
heterochronous isotransplantation was developed. In this
experimental procedure, the SOL or EDL muscles of young inbred
Lewis rats are grafted either into the host EDL or SOL muscles
of adult rats of the same strain with normal or experimentally
altered thyroid status. To estimate the extent of fiber type
transitions in the transplanted muscles, the SOL and EDL muscle
from the unoperated leg and unoperated muscles from the operated
leg could be legitimately used as controls, but only when the
experimental procedure itself does not affect these muscles. To
verify this assumption, we have compared the fiber type
composition and the MyHC isoform content of unoperated
contralateral SOL and EDL muscles and ipsilateral unoperated SOL
muscle of experimental rats after unilateral isotransplantation
into the host EDL muscle with corresponding muscles of the naive
rats of the same age and strain. We provide compelling evidence
that the unilateral heterochronous isotransplantation has no
significant effect on the fiber type composition and the MyHC
isoform content of unoperated muscles of experimental animals.
Hence, these muscles can be used as controls in our grafting
experiments.
Key words
Rat hind limb muscles • Muscle fiber phenotype • Stereology •
Immunocytochemistry • Gel electrophoresis • Influence of surgery
• Muscle transplantation
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