Author/Editor		Soukup, Tomaš; Zacharova, Gisela; Smerdu, Vika
Title		Fibre type composition of soleus and extensor digitorum longus muscles in normal female inbred Lewis rats
Type		članek
Source		Acta Histochem
Vol. and No.		Letnik 104, št. 4
Publication year		2002
Volume		str. 399-405
Language		eng
Abstract		We have analysed the fibre type composition of soleus and extensor digitorum longus (EDL) muscles of normal female 4-6-month-old inbred Lewis rats. This rat strain is used in our ongoing study of the effects of thyroid hormone on myosin heavy chain (MyHC) isoform expression. On the basis of the mATPase reaction, soleus muscles contained 96.1 ± 2.9% of type 1 fibres supplemented by 2A fibres. EDL muscles contained type 1 (5.5 ± 1.0%), type 2A (18.8 ± 1.7%) and type 2B (75.7 ± 2.2%) fibres. Immunohistochemical analysis and SDS gel electrophoresis confirmed that most fibres in the soleus muscle expressed the type 1 (slow) MyHC isoform and that only a small proportion of fibres expressed the fast 2a MyHC isoform. Immunohistochemical analysis and SDS gel electrophoresis demonstrated that almost half of the 2B fibres of EDL muscles expressed the 2x/d MyHC isoform. In both muscle types, many fibres expressed more than one MyHC isoform. The content of slow fibres in the soleus muscle of female inbred Lewis rats was slightly higher than that reported for Wistar rats, but was considerably higher than that of Sprague-Dawley rats, whereas substantial differences were not found in the proportion of slow and fast fibre types in EDL muscles in these strains.
Descriptors		MUSCLE, SKELETAL MUSCLE FIBERS, FAST-TWITCH MUSCLE FIBERS, SLOW-TWITCH MYOSIN HEAVY CHAINS IMMUNOHISTOCHEMISTRY ELECTROPHORESIS, STARCH GEL ADENOSINE TRIPHOSPHATE RATS, INBRED LEW RATS, WISTAR RATS, SPRAGUE-DAWLEY RATS, INBRED F344