M. Eyüp ALTUNKAYNAK, B. Zuhal ALTUNKAYNAK, Deniz ÜNAL, Özgen VURALER, Bünyami ÜNAL

Morphological Alterations of sciatic nerve during development from rat fetuses to adults: A Histological, stereological and Embryological study

Bu çalışmada, 16 ve 20 günlük sıçan fetüsleri, yeni doğan ve 5 haftalık erişkin sıçanlardan elde edilen siyatik sinirlerin myelinli akson sayıları hesaplandı. Çalışma için 16 ve 20 günlük fetüslerin yanı sıra yeni doğan ve 5 haftalık erişkin sıçanlar kullanıldı. Çalışma yapılırken cinsiyet farkı dikkate alınmadı. Anestezi altındaki deneklerden siyatik sinir örnekleri çıkarıldı ve myelinli akson sayıları da hesaplandı. Aynı zamanda siyatik sinir örnekleri histolojik olarak ta incelendi. Yirmi günlük sıçan fetüslerinden elde edilen siyatik sinirlerindeki akson sayısı 16 günlük fetüslerdekine kıyasla %249 artmıştı. Yeni doğanlardan elde edilen siyatik sinirlerindeki akson sayısı yirmi günlük sıçan fetüslerindekine kıyasla %56 azalmıştı. Bu çalışmadan elde edilen histolojik sonuçlar stereolojik sonuçlar ile paralellik göstermekteydi. Yirmi günlük fetüslerde 16 günlük fetüslere kıyasla daha fazla myelinli akson vardı. Yeni doğan siyatik sinirlerinden elde edilen kesitlerde ise 20 günlük fetüslerinkine kıyasla daha az myelinli akson görüldü. Ek olarak en fazla myelinli akson sayısı 5 haftalık erişkinlerden elde edilen siyatik sinirlerde görüldü. Bu çalışmadan elde edilen sonuçlar ışığında, gebeliğin son günlerinde yeni doğan grubuna kıyasla myelinli aksonların azaldığı; fakat postnatal dönemde erişkine ulaşana değin myelinli akson sayısının arttığı kanaatine varılmıştır.

Anahtar Kelimeler:

miyelin, embriyoloji, embriyonik gelişim, doku bilimi, sinir dokusu, sinir sistemi, periferal sinirler, sıçan, ışık mikroskopisi

Siyatik sinir gelişimi esnasında görülen morfolojik değişimlerin sıçan model üzerinde araştırılması: Histolojik, Stereolojik ve Embriyolojik bir çalışma

Myelinated axon numbers of the sciatic nerves which were obtained from 16 and 20 days foetuses, newborn and 5 weeks ages rats were estimated in this study.. In all groups gender factor was not considered. Following induction of anaesthesia, the sciatic nerves were removed and myelinated axon numbers were estimated. Sciatic nerve samples were also histologically analyzed. Overall, there was a 249% increase in the total number of myelinated axons in the sciatic nerves obtained from 20 days rat foetuses as compare to 16 days foetuses. Axon number in sciatic nerves got from newborn rats was decreased 56% as compare to twenty days foetuses. Histological results in this study were parallel to our stereological results. There were more myelinated axons in 20 days foetuses than in 16 days foetuses. It was also detected lesser myelinated nerve in sections obtained from newborn sciatic nerve than to 20 days foetuses. Moreover; the most myelinated axon number was observed in sciatic nerve got from 5 weeks ages adult rats. In view of these results, this study indicated that myelinated axons were decreased in the last a few days of pregnancy as compare to newborn group, whereas myelinated axon numbers were increased during postnatal ages till 5 weeks adult ages.

Keywords:

myelin, embryology, embryonic development, histology, nerve tissue, nervous system, peripheral nerves, rats, light microscopy,

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