A study on ovine muscle development

Koyunda kas ontojenisi üzerine çalışıldı. Gebelik yaşları (gy) 48 ile 125 arasında değişen 23 adet tekiz fötusmezbahadan toplandı. Fötusların ağırlıkları ve baş-kuyruk mesafeleri ölçülerek gebelik yaşları tahmin edildi.Semitendinosus kası (ST) veya çok küçük olan fötuslardan tüm arka bacak disekte edilerek alkali- adenozin trifosfataz(ATPaz) ve yavaş-miyozin ağır zincir (MHC) antikoru ile boyandı. Ayrıca, kesitler elektron mikroskopta (EM)incelendi. Histokimyasal, immunohistokimyasal ve EM çalışmalarına dayanarak kalitatif bulgular elde edildi.Sonuçlar, bazı sekonder liflerin çok erken dönemde yavaş MHC ekspresyonu yaptıklarını gösterdi. Büyük, yavaşMHC eksprese eden primer liflerin çevresinde oluşan bu küçük, yavaş MHC ekspresyonu yapan sekonder lifler 52.günde oluşmaya başlar; yaklaşık 69. günde çapları iyice artar ve yaklaşık 87. günde göç ederek ikinci generasyonsekonder liflerin (tersiyer) oluşumu için çerçeve görevi görürler. Gelişmiş geç dönem koyun fötusunda görülen büyük,merkezi ve yavaş MHC eksprese eden (alkali ATPaz ile düşük yoğunlukta da boyanan) liflerin bir kısmının aslındasekonder lifler olabileceği sonucuna varıldı.

Koyunda kas gelişimi üzerine bir çalışma

The ontogeny of ovine muscle was studied. 23 single fetuses aged between 48 and 125 days of gestation (dg) werecollected from abattoirs. The weight and crown-rump length of fetuses were measured and gestational age wasestimated. Semitendinosus muscle (ST) or hind limbs (for smallest fetuses) were dissected and stained for alkali-stableATPase and slow myosin heavy chain (MHC) antibody and also examined under the electron microscope (EM). Basedon histochemical, immunohistochemical and electron microscopy study, qualitative findings were obtained. Theresults suggested that some secondary fibres early express slow MHC. These small, slow expressing secondary fibresadjacent to the large, slow expressing primary fibres began to occur at 52 dg and these increased in size at around day69 and then migrated around 87 dg to act as a scaffold for the next generation of secondary (tertiary) fibres. Weconclude that some of the large, central, slow expressing (also less intensely stained with alkali-ATPase) fibres at nearterm sheep fetus might be secondary fibres.

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