Oxidative potential in developing rat diaphragm, EDL, and soleus muscle fibers

Abstract

To examine the effect of postnatal development on changes in oxidative potential of fibers of specific types (I, IIa, IIb, and IIc) in the rat diaphragm, determinations of succinate dehydrogenase (SDH) activity were made using microphotometric measures of optical density. Samples of the costal region of the diaphragm were extracted from 56 male Wistar rats ranging in age from 8 to 85 days and subgrouped into seven developmental periods (1, 2, 3, 4, 6, 9, and 12 wk). For type I fibers, increases of 17% (P less than 0.05) in SDH activity occurred during 2nd wk, remained elevated through 4th wk, and increased further (P less than 0.05) to 137% of 1-wk values by the end of 6th wk. No further increases were noted between 6 and 12 wk. A similar maturational trend was evident for type IIa fibers, although SDH activities remained higher throughout development when compared with type I fibers. In contrast, SDH in type IIb fibers, although increasing by 14% during the first two measurement weeks (P less than 0.05), declined from 6 to 9 wk before ultimately reaching a value similar to 3 wk. SDH activity was also assessed in a typical slow- (soleus) and fast-twitch (extensor digitorum longus, EDL) muscle of the hindlimb to contrast their development with that of the diaphragm. Generally, SDH in type I and IIa fibers was approximately 40 and 20% higher, respectively, in the diaphragm than in matched fiber types in the other muscles throughout development (diaphragm greater than EDL greater than soleus).(ABSTRACT TRUNCATED AT 250 WORDS)

Differential adaptations during growth spurt and in young adult rat muscles

“…As in most studies regarding age effects, the present results indicate a fast-to-slow fibre-type transition in soleus muscle, whereas no modification in fibre-type distribution was observed in EDL muscle (Smith et al, 1988;Ishihara and Taguchi, 1991;Sugiura et al, 1992;Konishi et al, 2000;Punkt et al, 2004).…”

“…Fibre-type differentiation is one useful example of this complex period. As a matter of fact, soleus muscle shows gradual fastto-slow fibre differentiation and extensor digitorum longus (EDL) muscle a type IIA-to-IIB differentiation (Smith et al, 1988;Umezu et al, 1992). Then at weaning age, skeletal muscles of rats have a well-defined pattern of fibre type, which are in agreement with their functional profile, e.g.…”

“…Indeed, fibre-type differentiation does not take place to the same extent in the slow soleus muscle and the fast EDL muscle. For the soleus muscle, numerous authors reported a further increase in slow-twitch fibres to the detriment of fast-twitch fibres (Ishihara and Taguchi, 1991;Konishi et al, 2000;Punkt et al, 2004), whereas for the fast EDL muscle the fibre-type profile is already established (Smith et al, 1988;Sugiura et al, 1992;Yamaguchi et al, 1993;Punkt et al, 2004).…”

Skeletal Muscle Characteristics of Rats with Obesity, Diabetes, Hypertension, and Hyperlipidemia

“…In the rat soleus muscle, type A and type C fibers have significantly higher oxidative enzyme activities than type fibers 3,21,44) . In this study, the mRNA expression level of PGC-1 in the soleus muscles of the GK group was lower than that of the WR group (Fig.…”

Histochemical profiles of fibers in the rat tibialis anterior muscle during early postnatal development.

“…Furthermore, F fibers consist of two subtypes with oxidative and glycolytic enzymes: fibers that stain darkly for both oxidative and glycolytic enzymes (FOG), and fibers that stain lightly for oxidative enzymes and darkly for glycolytic enzymes (FG) (PETER et al, 1972). Previous studies (KUGELBERG, 1976;SILLAU and BANCHERO, 1977;RUBINSTEIN and KELLY, 1978;SMITH et al, 1988) have observed that the histochemical differentiation and the type shift of muscle fibers in a muscle occurs during postnatal development. However, there are only a few detailed investigations on the histochemistry of muscle fibers during the early developmental stage.…”