Pengaruh tenotomi terhadap perkembangan musculus soleus dan musculus extensor digitorum longus Rattus norvegicus yang diberi T3 (triiodotironin)

Abstract

Muscle fiber type can change because of the change in the functional need and other signs.Motoneuron activity
pattern of the locomotor systemchanges during the development.During this development type I fibers percentage
increases in the slowmuscle, but decreases in the fastmuscle. Treatment with T3 decreases type I fibers
percentage without influencing the muscle fibers developmental stages. Thus, it is thought that motoneuron
involves in the mechanism of action of T3on the muscle fibers. Tenotomy that inactivates the muscle without
interrupting the flow of neurotrophic factor to themuscle fibers, can also changesmuscle fibers type. The aim
of this experiment is to revealed the interaction between the effect of tenotomy and T3 treatment on the development
of rats SOL (soleus) and EDL (extensor digitorumlongus)muscles. Thus, the role ofmotoneuron on the
mechanismof action of T3 can be known.Seven, 17 and 23-day-oldmale rats are divided into two groups.Group
I was injectedwithT3 400μg/kgBB intraperitoneally every other day.Group IIwas injectedwith physiologic saline
solution in the same way as group I. In the beginning of the experiment SOL and EDL in one limb of all rats is
tenotomized. Three, 5 or 7 week after the treatment themuscles were examined. In both groups, size, weight
and fibers type I percentage in the tenotomized limb are significantly lower than the untenotomized. Therewere
only slight changes in the EDL.Thus, the effect of tenotomy and T3 treatment are strengthening each other. It is
concluded thatmotoneuron has a role in themechanismof action of T3 on themuscle fibers. The role is thought
through its effect on neutrotrophic substance