Present work is aimed at studying the effects of natural bioactive
sphingomyelin derivatives, on normal and denervated
slow-twitch skeletal muscle. The effects on fibre cross sectional
area and myosin heavy chains composition of sphingosine
(SPH), sphingosine 1-phosphate (S1P) and sphingosylphosphorylcholine
(SPC) were studied. Denervation was bilaterally
performed cutting the sciatic nerve at the level of trochanter
in adult rats. A group of animals was used as controls.
Sphingolipids were continuously released by a mini-osmotic
pumps implanted subcutaneously in the scapular region and
connected by a catheter to the left (control or denervated) soleus
muscles. Supplementation of SPC to adult control soleus
muscle, produced significant atrophy of fibres and small
changes to fibre type composition. No significant effects of
SPH and S1P were found. In contrast, SPH and, to a smaller
extent, S1P reduced the atrophy and the slow-to-fast transformation
produced by 7-14 days of denervation. Preliminary
results indicate that these sphingolipids may exert their action
by reducing the overall muscle apoptosis and by activating
satellite cells