ACTA FAC MED NAISS 2008; 25 (1): 41-45

Original article

IDENTIFICATION OF FIBER TYPES IN RAT SKELETAL MUSCLE BASED ON THE USE OF CATIONIC DYES IN MYOFIBRILLAR ADENOSINE TRIPHOSPHATASE REACTION
 

Irena Dimov¹,
Desanka Tasic-Dimov²

¹Institute of Immunology, Faculty of Medicine in Nis

²Department of Pathology, Clinical Center Nis

SUMMARY

The histochemical reaction for myofibrillar adenosine triphosphatase (mATPase) is widely used method in typing skeletal muscle fibers. The mATPase reaction allows a qualitative and quantitative evaluation of fiber types in normal, diseased, or experimentally altered muscles.        

The aim of this study was to investigate the reproducibility and validity of cationic dyes' use in the mATPase reaction for identifying fiber types in the rat soleus muscle by the method proposed by Doriguzzi et al.

The soleus muscle was removed from 10 adult Wistar albino rats of both sexes under ether anesthesia. Serial frozen cross-sections 10 μm thick were prepared and reacted for mATPase after preincubation at pH 9.4, 4.5 and 4.3, and for modified mATPase with the use of Toluidine blue (TB) and Methylene blue (MB) in post-incubation treatment of sections.

The mATPase reaction demonstrated by TB and MB displayed a clear cut differentiation of muscle fiber types corresponding to type I, IIA and IIC fibers, obtained by mATPase reaction with ammonium sulfide. The method based on the use of cationic dyes in mATPase reaction appears to be fast, reproducible and valid.

However, in our experience, the intensity of coloration of muscle fibers decreased by time so that the distinction between fiber types become difficult, which stands for the main disadvantage when compared to  the conventional mATPase method.

Key words: fiber types, rat skeletal muscle, mATPase histochemistry, ammonium sulfide, cationic dyes