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

Yenidoğan rat beyninde gelişim döneminde yüksek yerçekimine bağlı zonula occludens (Tight junction) yapısal değişikliklerinin incelenmesi

Uzayda yaşam ve yüksek yerçekiminin osteoporosis gibi hastalıklarda kullanılma olasılığı, hem düşük (mikrogravite)hem de yüksek yerçekimi (hipergravite) etkisinin ve kullanılan mekanizmaların aydınlatılması için birçok çalışmaya konu olmaktadır. Beyinde tight junction (TJ) denilen zonula occludens'ler kan beyin bariyerinin (KBB) oluşumu nedeni ile ayrı bir önem taşımaktadır. Bu çalışmada hipergravitenin (2G) ve rotasyonun yenidoğan Wistar albino ratlarda merkezi sinir sisteminin KBB'ni oluşturan zonula occludens (TJ) üzerine etkisi araştırıldı.Çalışmada 90 adet yenidoğan Wistar albino rat kullanıldı. Yavru ratlar kontrol, rotasyon (G) ve hipergravite (2G) olmak üzere 3 gruba ayrıldı. Bir grup kontrol olarak ayrılırken; bir grup yerçekimi ivmesine eşit rotasyona (G), diğer grup ise yerçekimi ivmesinin yaklaşık 2 katı (2G) ve günde 6 saat süreyle rotasyona maruz bırakıldı. Her grupta 6 yavru rat olacak şekilde postnatal 3., 7., 15., 21. ve 28.günlerde yavrular eter anestezisi altında %10 formalin perfüzyonu ile fikse edilip, dekapite edildi ve beyinleri çıkarıldı. Parafin kesitlere immunohistokimyasal olarak zonula occludens ZO-1 ve occludin boyamaları uygulandı. Sonuçlar ışık mikroskobunda değerlendirildi. ZO-1 ve occludin proteinlerinin gelişim sürecine parelel olarak ortaya çıktıkları ancak, rotasyon ile 2G düzeyinde ve uygulanan süre içinde, ışık mikroskobik düzeyde yapılan incelemede proteinlerin ortaya çıkması ve dağılımı açısından kontrol grubuna göre bir fark olmadığı saptandı.

Anahtar Kelimeler:

Sıçan, Wistar, Hücre membranı, Yüksek yerçekimi, Beyin, Kan-beyin bariyeri

A study on the structural changes of zonula occludens (Tight junction) by hypergravity during developmental period of newborn rat brain

The realization of a long lasting dream of living in outer space and the potential use of hypergravity for the treatment of ailments such as osteoporosis prompted extensive research on the effects of microgravity and hypergravity on the organisms and to shed light to the mechanisms associated with these. Zonula occludens, ZO also known as tight junctions in the brain are particularly important since they have a role in the formation of blood-brain barrier (BBB). In this study we examined the effects of hypergravity (2G) and rotation on zonula occludens. (TJ).Ninety newborn Wistar albino rats are used in the study. Rotation group were subjected to centrifugation that is equivalent to the gravitational force (G) while hypergravity group underwent centrifugation that was twice as much as the gravity for 6 hours a day. Under ether anesthesia, rats in each subgroup were perfused with 10% formalin, decapitated and the brains were removed. Paraffin sections were immunohistochemically stained with ZO-1 and occludin dyes and examined under a light microscope. ZO-1 and occludin proteins appeared normally during the course of the development. Light microscopic examination did not reveal any differences between the control group and rotation hypergravity groups with regard to the appearance or the distribution of these proteins.

Keywords:

Rats, Wistar, Cell Membrane, Hypergravity, Brain, Blood-Brain Barrier,

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