Effects of testosterone replacement therapy on skeletal muscle after spinal cord injury.
METHODS
Randomized control.


OBJECTIVE
To examine the effects of testosterone replacement therapy (TRT) on skeletal muscle 11 weeks after complete SCI.


METHODS
Athens, Georgia USA.


METHODS
Soleus (SOL), gastrocnemius (GA), tibialis anterior (TA), vastus lateralis (VL) and triceps brachii (TRI) muscles were taken from twelve young male Charles River rats 11 weeks after complete SCI (T-9 transection, n=8) or sham surgery (n=4). Rats received either TRT (two 5 cm capsules, n=4) or empty capsules (n=8) implanted at surgery. Muscle samples were sectioned and fibers analyzed qualitatively for myosin ATPase and quantitatively for succinate dehydrogenase (SDH), alpha-glycerol-phosphate dehydrogenase (GPDH) and actomyosin ATPase (qATPase) activities using standard techniques.


RESULTS
SCI decreased average fiber size (49+/-4%) in affected muscles and the percentage of slow fibers in SOL (93+/-3% to 17+/-2%). In addition, there was a decrease in SDH and an increase in GPDH and qATPase activities across the four hind-limb muscles of the SCI animals. Fiber size in the TRI was increased (31+/-2%) by SCI while enzyme activities were not altered. Average fiber size across the four hind limb muscles was decreased by only 30% in TRT SCI animals and their SOL contained 39+/-2% slow fibers. TRT also attenuated changes in enzyme activities. There was no effect of TRT on the TRI relative to SCI.


CONCLUSIONS
TRT was effective in attenuating alterations in myofibrillar proteins during 11 weeks of SCI in affected skelatal muscles.


BACKGROUND
Supported by a grant from The National Institutes of Health (HD-33738) and HD-37645 to KV, and HD-39676 to GAD.
Gregory
C M
CM
Department of Physical Therapy, Texas Women's University, Houston, Texas, TX 77030, USA.
Vandenborne
K
K
Huang
H F S
HF
Ottenweller
J E
JE
Dudley
G A
GA
D000704:Analysis of Variance; D000818:Animals; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D051381:Rats; D013119:Spinal Cord Injuries / Q000473:pathology*; D013739:Testosterone / Q000494:pharmacology*
D013739:Testosterone