Dnmt3a and Dnmt3b expressions decrease after cryopreservation and re-transplantation of ovarian tissue

Abstract

Objective DNA methylation includes maintenance and de novo methylation process that are catalyzed by DNA methyltransferase (Dnmt) enzymes and these enzymes possess crucial roles in methylation of genes associated with the development of ovarian follicles. The aim of this study is to evaluate whether expression of Dnmt3a and Dnmt3b protein levels change after cryopreservation and re-transplantation of ovarian tissue in rats. Methods Four groups were designed as; fresh control (FC), frozen/thawed (FT), fresh re-transplanted (T), and frozen/thawed and re-transplanted (FTT). Slow freezing was used to cryopreserve the ovarian tissue pieces and expression of Dnmt3a and Dnmt3b proteins was assessed by immunohistochemistry. Result Expression of Dnmt3a and Dnmt3b significantly decreased in ovarian follicles in FT, T and FTT groups when compared FC. Conclusion Expression of Dnmt enzymes has been altered both after cryopreservation alone and following re-transplantation cycles which may lead to disturbed DNA methylation processes during rat folliculogenesis

Keywords

• DNA methylation
• Dnmt enzymes
• ovarian tissue cryopreservation
• fertility preservation

Ovaryum kriyoprezervasyonu ve yeniden transplantasyondan sonra Dnmt3a ve Dnmt3b protein ifadelerinin düşmesi bu süreçte DNA metilasyonunun bozulduğunu gösterir

Öz

Amaç DNA metilasyonu sürdürme ve de novo metilasyon süreçlerini içerir ve DNA metiltransferaz (Dnmt) enzimleri tarafından katalizlenir, ovaryum foliküllerinin gelişimi ile ilişkili genlerin metilasyonunda önemli role sahiptir. Çalışmamızın amacı, sıçanlarda ovaryum dokusunun kriyoprezervasyonu ve yeniden transplantasyonu sonrasında Dnmt3a ve Dnmt3b protein düzeylerinin ekspresyonunun değişip değişmediğini değerlendirmektir. Yöntemler Kontrol (K), donmuş/çözdürülmüş (DÇ), transplante edilmiş (T) ve dondurulmuş/çözdürülmüş ve yeniden transplante edilmiş (DÇT) olmak üzere dört grup oluşturuldu. Ovaryum doku parçalarını dondurmak için yavaş dondurma tekniği kullanıldı ve Dnmt3a ve Dnmt3b proteinlerinin ekspresyonu immünohistokimya yöntemi ile değerlendirildi. Result K ile karşılaştırıldığında, DÇ, T ve DÇT gruplarında ovaryum foliküllerinde Dnmt3a ve Dnmt3b ekspresyonu önemli ölçüde azaldı. Sonuç Hem kriyoprezervasyon hem de yeniden transplantasyondan sonra değişen Dnmt enzimlerinin ekspresyonu sıçan folikülogenezi sırasında DNA metilasyonu süreçlerinin bozulması ile ilişkili olabilir.

Anahtar Kelimeler

• DNA metilasyonu
• Dnmt enzimleri
• ovaryum doku kriyoprezevasyonu
• fertilitenin korunması

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