The Effects of Ovarian Vitrification on Mitochondrial Fusion (MFN-1, MFN2 and OPA-1), Fission (DNM-1), Mitophagy (PARKIN, PINK-1) and Transport (MIRO-1, MILTON) Proteins

Abstract

Objective: Ovarian cryopreservation is a useful alternative for fertility preservation in assisted reproductive technologies. In spite of many advances in the vitrification procedure, this technique is still considered experimental. Therefore in this study, we aimed to investigate the expressions of mitochondrial fusion (MFN1, MFN2 and OPA1), fission (DRP1), mitophagy (PARKIN, PINK1) and transport (MIRO-1, MILTON) proteins in ovarian tissues by qPCR technique after vitrification. Materials and Methods: To investigate the mitochondrial dynamics after vitrification, the ovaries were recovered from 6-8 week old healthy female mice (No: 12) and were divided into vitrification and control groups. Vitrification carried out using ethylene glycol, dimethylsulfoxide and sucrose. After total RNA isolation from ovaries in control and vitrification groups, qPCR technique was performed to determine the expression rate of target genes. The relative gene expressions of the target genes were evaluated according to 2−∆∆Ct method. Results: Histological evaluation revealed that ovaries in the control group were shown normal morphology while the tissue integrity of the ovaries in the vitrification group is disrupted, some follicles are degenerated and granulosa cells were shed into antrum. According to our qPCR results, outer membran fusion proteins MFN1 gene expression decreased 1,12 fold and inner membran protein OPA-1 increased 1,36 fold in the vitrification group compared the control group. The mitochondrial fission protein DRP-1 gene expression increased 1,20 fold in the vitrification group. The mitophagy proteins PINK-1 and PARKIN genes expressions decreased 1,34 and 3,75 fold respectively in the vitrification group. The transport proteins; MIRO-1 gene expression decreased 1,16 fold but MILTON (TRAK-1) gene expression sharply increased 2,28 fold compared the control group. Conclusion: The alternation of the mitochondrial dynamics related gene expressions may lead a decrease in the mitochondrial function during the ovarian vitrification and may reduce the potential of oocyte maturation and embryo development