TUNCAY VAROL, M. İbrahim TUĞLU, Seda VATANSEVER, Enis CEZAYİRLİ, Ertuğrul TATLISUMAK, Ceyda HAYRETDAĞ

Yüksek yerçekimi koşullarının yenidoğan rat beyin gelişimine etkisinin stereolojik, morfolojik ve histokimyasal açıdan incelenmesi

Yeryüzünde yaşayan tüm canlılar genetik faktörlerin olduğu kadar, çevresel faktörlerin de etkisi altındadır. Bu çevresel faktörlerin belki de en önemli ve sürekli olanı yerçekimi (gravite)' dir. Gravitenin artması (hipergravite) ise uçak yolculuk¬ları sırasında meydana gelen parabolik uçuş esnasında ya da uzaya yolculuk sırasında gerçekleşmektedir. Deneysel olarak özellikle hipergravitenin ve rotasyonun yenidoğan Wistar albino ratlarda merkezi sinir sisteminin gelişimine ve miyelinizasyon sürecine yaptıkları etki araştırıldı. Deney düzeneği olarak hızı ayarlanabilir rotasyon aleti kullanıldı. Ro¬tasyon aletinin kol uzunluğu 144 cm ve dönme hızı G grubu için 25 devir/dk, 2G grubu için 36 devir/dk olarak uygulandı. 90 adet wistar albino yenidoğan rat kullanıldı. Yenidoğan ratlar kontrol, G ve~2G olmak üzere 3 gruba ayrıldı. G ve 2G grupları günde 6 saat rotasyona maruz bırakıldı ve 3., 7., 15., 21. ve 28. günlerde eter anestezisi altında % 10 formalin ile perfüzyon fiksasyonu uygulandıktan sonra dekapite edilip, beyinleri çıkarıldı. Hazırlanan parafin bloklardan 8ju luk kesitler alındı. Solochrome cyanine ve PAS ile boyanan kesitler ışık mikroskopu altında değerlendirildi. Ayrıca seri kesitlerden alınan görüntülerde Cavalieri metodu ile stereolojik ölçüm yapıldı. Elde edilen verilere göre rotasyon ve 2G seviyesinde hipergravitenin, ilk 4 haftalık periyotta ışık mikroskopik seviyede, miyelinizasyon sürecine ve beyin gelişimine belirgin bir etki yapmadığı sonucuna varıldı.

Anahtar Kelimeler:

Sıçan, Wistar, Beyin, Yüksek yerçekimi, Süt çocuğu, yenidoğan, Sinir sistemi

Stereological, morphological and histochemical study on the effect of hypergravity on newborn rat brain

All terrestrial creatures are affected by environmental factors as well as genetic factors. Gravity is probably the most important and continuous environmental factor we all are exposed to. Hypergravity is encountered during parabolic flights, or during the launch of space shuttle, and sometimes during extreme acceleration in a vehicle. The effects of hypergravity and centrifugation on the development and myelinisation processes of central nervous system of newborn wistar albino rats have especially been investigated. A variable speed centrifugator with a radius of 144 cm was used in the experiment. Ninety newborn Wistar albino rats were assigned equally to control, G and 2G groups. G and 2G groups were subjected to centrifugation at a speed of 25 rpm and 36 rpm respectively for 6 hours a day. Following ether anesthesia, equal number of rats from each group were perfused with 10% formalin at postnatal 3rd, 7th, 15th, 21st and 28th days and decapitated. Brains were removed and embedded in parafin. Eight micrometer thick sections were stained with Solochrome cyanine and PAS and examined under light microscope. Digital images were obtained from serial sections for Cavalieri based stereologic estimations. The results suggested that centrifugation (G) and hypergravity (2G)caused significant effect neither on myelinisation process nor brain development light microscopically in the first 4 weeks of postnatal period.

Keywords:

Rats, Wistar, Brain, Hypergravity, Infant, Newborn, Nervous System,

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