Effect of Selenium on Oocyte Maturation and Viability in vitro in Mouse

체외 배양시 생쥐난자의 성숙과 생존에 미치는 Selenium의 영향

  • Choi, Eun-Jin (Department of Life Science, Chungbuk National University) ;
  • Hong, Soon-Gab (Department of Life Science, Chungbuk National University) ;
  • Kim, Hae-Kwon (Department of Biotechnology, Seoul Women's University) ;
  • Yoon, Yong-Dal (Department of Life Science, College of Natural Science, Hanyang University) ;
  • Lee, Joon-Yeong (Department of Life Science, Chungbuk National University)
  • Published : 2006.10.01

Abstract

The present experiment was performed to confirm the effects of selenium on maturation and viability of mouse oocyte. Maturation of oocytes was observed by microscope, Germinal vesicle breakdown(GVBD) and polar body formation(PB) were confirmed at 2.5, 13 hours after in vitro culture. Viability of oocytes was observed by microscope. Normal and abnormal oocytes were distinguished by morphological change in vitro culture for 72 hours. Glutathione(GSH) content of collected oocytes from individual stage also was measured by glutathione assay using spectrophotometer. The results obtained were as follows; The low concentration of selenium($0.005\;{\mu}g/mL{\sim}0.5\;{\mu}g/mL$) increased the maturation rate of germinal vesicle(GV) oocytes to GVBD and PB oocytes. The high concentration of selenium($5\;{\mu}g/mL$) decreased the maturation rate. The low concentration of selenium increased the viability rate of PB oocytes. The high concentration of selenium did not affect the viability rate. The low concentration of selenium increased the GSH content in PB oocytes. The high concentration of selenium decreased GSH content. GSH content in PB oocyte was much higher than that in GVBD oocyte. The results indicate that the low concentration of selenium increases the maturation rate by helping quality elevation of oocyte and minimizing damages of oxidative stress generated from metabolism process. The low concentration of selenium also increases the viability rate by increasing GSH content.

본 실험은 생쥐 난자의 성숙과 생존에 미치는 selenium의 영향을 알아보고자 수행하였다. 난자의 성숙은 현미경을 통해 관찰하였으며, 핵막 붕괴(germinal vesicle breakdown, GVBD)와 극체 형성(polar body formation, PB)은 체외 배양 시작 후 각각 2.5, 13시간에 확인하였다. 난자의 생존은 72 시간동안 체외 배양하면서 형태학적 차이로 정상 난자와 비정상 난자를 판별하였다. 또한 각 단계별로 수집된 난자의 glutathione(GSH) 함량은 spectrophotometer를 사용하여 glutathione assay로 측정하였다. 결과는 다음과 같다; 저농도의 selenium($0.005\;{\mu}g/mL{\sim}0.5\;{\mu}g/mL$)은 핵막 붕괴율과 극체 형성률을 증가시켰지만, 고농도의 selenium($5\;{\mu}g/mL$)은 감소시켰다. 저농도의 selenium은 극체 형성 시기 난자의 생존율을 증가시켰지만, 고농도의 selenium은 대조군과 별 차이가 없었다. 저농도의 selenium은 난자내 GSH 함량을 높게 유지시켰지만, 고농도의 selenium은 GSH 함량을 감소시켰다. 또한 극체 형성 시기 난자내 GSH 함량은 핵막 붕괴 시기 난자에 비해 높았다. 본 실험으로 볼 때, 저농도의 selenium은 대사과정에서 발생하는 oxidative stress에 의한 손상을 감소시킴으로써 난자의 질적 향상을 도우며, 성숙률을 증가시키는 것으로 사료된다. 또한 저농도의 selenium은 난자내 GSH 함량을 증가시켜 극체 형성 난자의 생존율을 증가시키는 것으로 사료된다.

Keywords