Comparative Functional Analysis of the Malate Dehydrogenase(Mor2) during in vitro Maturation of the Mouse and Porcine Oocytes

체외성숙 과정 중 생쥐와 돼지 난자의 Malate Dehydrogenase(Mor2)의 기능에 대한 비교 분석

  • Kim, Eun-Young (CHA Research Institute, Fertility Center, CHA General Hospital) ;
  • Kim, Kyeoung-Hwa (CHA Research Institute, Fertility Center, CHA General Hospital) ;
  • Kim, Yun-Sun (Graduate School of Life Science and Biotechnology, Pochon CHA University College of Medicine) ;
  • Lee, Hyun-Seo (Graduate School of Life Science and Biotechnology, Pochon CHA University College of Medicine) ;
  • Kim, Yu-Nna (Graduate School of Life Science and Biotechnology, Pochon CHA University College of Medicine) ;
  • Lee, Kyung-Ah (CHA Research Institute, Fertility Center, CHA General Hospital)
  • 김은영 (차병원 여성의학연구소) ;
  • 김경화 (차병원 여성의학연구소) ;
  • 김윤선 (포천중문의과대학교 생명과학전문대학원) ;
  • 이현서 (포천중문의과대학교 생명과학전문대학원) ;
  • 김유나 (포천중문의과대학교 생명과학전문대학원) ;
  • 이경아 (차병원 여성의학연구소)
  • Published : 2007.12.30

Abstract

Contrast to mouse where its in vitro maturation rates are high without specific supplements or presence of the cumulus cells, there are some species, such as porcine, where its in vitro oocyte maturation rates are still very low. This comparative study was conducted to investigate the role of malate dehydrogenase(Mor2) during oocyte maturation by RNAi in the mouse and porcine. The Mor2 double-stranded RNA(dsRNA) was prepared speciesspecifically and microinjected into the cytoplasm of denuded germinal vesicle(GV) oocytes. Oocytes were cultured for 48 h(porcine) and 16 h(mouse) in M199 with 10% porcine follicular fluid, pyruvate, p-FSH, EGF, cystein, and estradiol-$17{\beta}$. We measured changes in oocyte morphology, maturation rates and mRNA levels after Mor2 RNAi. We confirmed gene sequence-specific knock down of Mor2 mRNA in both species after Mor2 RNAi. In contrast to our previous finding that mMor2 RNAi resulted in GV arrest in the mouse, we found that pMor2 RNAi resulted in MI arrest in denuded porcine oocytes(58%), but developed to MII(84.4%) in COCs. To determine whether this difference between mouse and porcine RNAi is due to differences in culture media, we cultured mouse oocytes in the M199 media for 16 h after mMor2 RNAi. Mouse oocytes were developed to MII stage(62%) and there was no statistical difference compared to that of non-injected(76.8%) and buffer-injected(73.3%) control groups. Therefore, we concluded that the mouse and porcine oocytes are having different metabolic systems in relation to malate dehydrogenase for oocyte maturation. This could be a basis for differences in maturation rates in vitro in two species. Further scrutinized studies on the metabolic pathways would led us in finding better culture system to improve oocyte maturation rates in vitro, especially in more challenging species like the porcine.