Expression of intermediate filaments at muscle insertions in human fetuses

Abstract

Desmin and vimentin are intermediate filaments that play crucial roles in the maturation, maintenance and recovery of muscle fibers and mesenchymal cells. The expression of these proteins has not been investigated extensively in human fetuses. In the present study, we examined the immunohistochemical expression of intermediate filaments in skeletal muscles of the head, neck and thorax in 12 mid-term human fetuses at 9-18 weeks of gestation. We also used immunohistochemistry to localize the expression of the myosin heavy chain and silver impregnation to identify the fetal endomysium. Expression of desmin and vimentin was already detectable in intercostal muscle at 9 weeks, especially at sites of muscle attachment to the perichondrium. At this stage, myosin heavy chain was expressed throughout the muscle fibers and the endomysium had already developed. Beginning with punctate expression, the positive areas became diffusely distributed in the muscle fibers. At 15-18 weeks, intermediate filament proteins were extensively expressed in all of the muscles examined. Expression at the bone-muscle interface was continuous with expression along the intramuscular tendon fibres. These results suggest that the development of intermediate filaments begins in areas of mechanical stress due to early muscle contraction. Their initially punctate distribution, as observed here, probably corresponds to the earliest stage of fetal enthesis formation.

Early fetal development of the rotator interval region of the shoulder with special reference to topographical relationships among related tendons and ligaments

“…There were around 100 sections for each shoulder. Most sections were stained with hematoxylin and eosin (HE), while some were subjected to immunohistochemical staining for vimentin (one of the intermediate filament components) because it is likely to be expressed at sites subjected to high mechanical stress 9 . The primary antibody used was rabbit polyclonal anti-human S100 protein (Dako Cytomation, Kyoto, Japan).…”

Medial Pterygoid initiated the Growth of the Mandible through Premature Muscle Contraction

“…The results showed that at ED 14.5, the MP has already more than one tendon, which is clearly shown by observing the expression patterns of desmin to integrate strongly in the future tendon. Besides, in human, desmin expression in between muscle tendon and then to the entire muscle fibers was found 15) . As early as ED 12.5, the desmin was localized in between the MP and future mandible.…”

“…Desmin is a muscle specific intermediate filament, linking myofibrils to each other at the level of Z band and it is also believed to link the myofibrils to the sarcolemma 7,8) . Moreover, desmin expression has been shown in the development of muscle, myoblast, myotubes, muscle fibers addition, desmin integration in cardiac and skeletal muscle during embryonic development is faster than in any other parts of the body 15,16) . Vimentin is similar to desmin intermediate filament,…”

Oblique cord (chorda obliqua) of the forearm and muscle-associated fibrous tissues at and around the elbow joint: a study of human foetal specimens

“…At the attachment site (insert of Figs. 2F; 3F), the muscle fibres of the FDP contained the so-called desmin-spots, suggesting muscle origin or insertion according to our previous study [3]. HE staining of the late stage foetuses showed the FDP origin from the capsule (Fig.…”