Vol.14, No 3, 2007 pp. 121 - 127
UC 599.323.4:591.473
MUSCLE FIBER TYPES AND FIBER MORPHOMETRY
IN THE SOLEUS MUSCLE OF THE RAT
Desanka Tasić Dimov¹, Irena Dimov²
¹Department of Pathology, Clinical Center, Faculty of Medicine, Niš
²Institute of Immunology, Faculty of Medicine, University of Niš
E-mail: desa@medfak.ni.ac.yu
Summary. Muscle fiber type composition, distribution and size of
fibers were investigated in the soleus muscle of young adult male and female
rats, using histochemical and morphometric methods, to determine whether
these parameters vary according to the sex of animals. Combined myofibrillar
ATPase (mATPase) and metabolic enzyme histochemistry were performed on
serial cross-sections from the belly region of muscle. Three fiber types
(I, IIA, and IIC) were identified on the basis of mATPase activity after
preincubation at pH values of 9.4, 4.5 and 4.3. The type IIC fibers, present
in a small number (about 4%), were included within the type IIA fiber class
for purposes of quantitative analysis. The fiber type composition of the
slow soleus muscle showed type I dominance (78%). There has been observed
a variation in the regional distribution of muscle fiber types. A relative
number of type IIA fibers increased towards the lateral part of the muscle,
and so did type IIC, but the general organization was not as regular as
those previously found in the fast tibialis anterior and tibialis posterior
muscles. The size of predominating fibers of type I was larger than of
IIA type fibers in the soleus muscles from the both groups. No significant
difference was detected between male and female rats in respect to the
morphometric parameters examined.
Key words: Fiber types, skeletal
muscle, myofibrillar ATPase, morphometry, rats
TIPOVI MIŠIĆNIH VLAKANA I MORFOMETRIJA
VLAKANA U MUSCULUS SOLEUSU PACOVA
Kratak sadržaj: Ispitivana je kompozicija tipova mišićnih vlakana,
njihova distribucija i veličina u m. soleusu mladih odraslih mužjaka
i ženki pacova, korišćenjem histohemijskih i morfometrijskih metoda,
da se utvrdi da li ispitivani parametri variraju prema polu životinje.
Na serijskim poprečnim presecima mišića primenjena je kombincija histohemijskih
metoda: miofibrilarna ATPaza (mATPaza) i enzimi metabolizma. Identifikovana
su tri tipa vlakana (I, IIA i IIC) na osnovu aktivnosti mATPaze nakon preinkubacije
pri pH 9,4; 4,5 i 4,3. Vlakna tipa IIC, koja su zastupljena u malom broju
(oko 4%), uključena su u grupu vlakana tipa IIA za potrebe kvantitativne
analize. Ispitivanje kompozicije tipova vlakana pokazalo je da u sporom
m. soleusu dominira tip I (78%). Zapažena je varijacija u regionalnoj
distribuciji tipova mišićnih vlakana. Idući prema lateralnom polu mišića
povećavao se relativni broj vlakana tipa IIA, kao i tipa IIC, ali generalna
organizacija nije bila tako regularna kako je prethodno utvrđeno za brze
mišiće, tibialis anterior i tibialis posterior. Veličina predominirajućih
vlakana tipa I bila je veća od vlakana tipa IIA u mišićima obe ispitivane
grupe. Nije utvrđena značajna razlika između mužjaka i ženki pacova
u ispitivanim morfometrijskim parametrima.
Ključne reči: tipovi vlakana,
skeletni mišić, miofibrilarna ATPaza, morfometrija, pacovi
