Ratlarda roziglitazon’un telomer dinamiğine etkisinin moleküler yöntemlerle araştırılması

Abstract

Roziglitazon; Tip II diabet tedavisinde kullanılan tiazolidinedion grubu bir ilaçtır. Bu grup ilaçlar, karbonhidrat ve lipid metabolizmasını kontrol eden genlerin ekspresyonunun düzenlenmesinde görev alan peroksizom proliferatör aktive reseptör-gama (PPARgama)’nın ligandı olarak rol oynarlar. Telomer; kromozom uçlarında bulunan özelleşmiş DNA ve protein kompleksinden oluşmaktadır. Omurgalılarda telomerik DNA, TTAGGG gibi, guaninden zengin dizelerden oluşur. Normal hücrelerde, her DNA replikasyon peryodunda, telomer 50–150 baz kısalır. Tamir edilemeyen oksidatif DNA hasarı da bu telomer kısalmasına katkıda bulunabilir. Literatürde, roziglitazonun telomer uzunluğuna etkisini gösteren bir çalışma bulunmamaktadır. Bu nedenle, çalışmamızda roziglitazonun telomer uzunluğuna etkisini araştırmayı amaçladık. Çalışmada 7–8 haftalık, 248-275 g arasında, 16 tane erkek Sprague-Dawley cinsi rat kullanıldı. Ratlar; her grupta dört tane olacak şekilde dört gruba ayrıldı ve 14 gün boyunca 0, 0,5, 1,0 ve 2,0 mg/kg dozlarında roziglitazon oral yoldan uygulandı. Rat karaciğer, ince bağırsak, pankreas dokuları ve
lenfositlerinden genomik DNA izolasyonu yapıldı. Numunelerde genom sayısını belirleyebilmek için tek kopya gen olarak 36B4 geni seçildi. 36B4 genine spesifik primerlerin kullanıldığı Q-PCR ile bir rat dokusundaki genom kopya sayısı bulundu. Rat genom standardı olarak kullanılan bu numune tüm numunelerdeki genom sayısını bulmak için kullanıldı. Tüm numunelerde telomer (T) ve 36B4 (S) için kantitatif PCR yapıldı. İki çalışmada ile elde edilen ürünler birbirine oranlarak her numune için T/S oranı daha sonra da bir kalibratör numune kullanılarak relatif T/S oranı hesaplandı. Ayrıca 10,2 kb telomer standardı kullanarak numunelerin telomer uzunlukları kilobaz olarak da hesaplandı. Farklı roziglitazon dozları verilen numuneleri kontrol grubları ile karşılaştırıldığımızda telomer uzunluğu açısından istatistiksel olarak anlamlı bir fark bulamadık (p>0,05). Bu sonuç, roziglitazonun farklı rat dokularında telomer kısalmasına yol açmadığını göstermektedir

Keywords

• PPAR-gama
• Thiazolidinedion
• Roziglitazon
• Telomer
• Oksidatif stres
• Kantitatif PCR

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