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

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