Stage-specific Expression of Lanosterol 14${\alpha}$-Demethylase in Mouse Oocytes in Relation to Fertilization and Embryo Development Competence

Song, Xiaoming;Ouyang, Hong;Tai, Ping;Chen, Xiufen;Xu, Baoshan;Yan, Jun;Xia, Guoliang;Zhang, Meijia

  • Received : 2008.02.27
  • Accepted : 2008.07.08
  • Published : 2009.03.01


Follicular fluid meiosis-activating sterol (FF-MAS) has been suggested as a positive factor which could improve the oocyte quality and subsequent embryo development after in vitro fertilization. However, FF-MAS is a highly lipophilic substance and is hard to detect in studying the relationship between MAS and quality of oocyte maturation. The present study focused on the expression of lanosterol 14${\alpha}$-demethylase (LDM), a key enzyme that converts lanosterol to FF-MAS, on mouse oocyte maturation and its potency on development. LDM expression was strong in gonadotropin-primed germinal vesicle stage oocytes, weak after germinal vesicle breakdown (GVBD), and then strong in MII stage oocytes. The LDM-specific inhibitor azalanstat significantly inhibited oocyte fertilization (from 79.4% to 68.3%, p<0.05). Also, azalanstat (5 to 50 ${\mu}M$) decreased the percentage of blastocyst development dosedependently (from 78.7% to 23.4%, p<0.05). The specific inhibition of sterol ${\Delta}14$-reductase and ${\Delta}7$-reductase by AY9944 accumulates FF-MAS and could increase blastocyst development rates. Additionally, in the AY9944 group, the rate of inner cell mass (ICM)/ total cells was similar to that of in vivo development, but the rate was significantly decreased in azalanstat treatment. In conclusion, LDM, the key enzyme of FF-MAS production, may play an important role in fertilization and early development of the mouse embryo, especially in vitro.


Mouse Oocyte;Lanosterol 14${\alpha}$-Demethylase;In vitro Fertilization;Early Embryo Development


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Supported by : National Natural Science Foundation of China