FSH抑制卵泡細胞之自我衰亡

FSH刺激granulosa cell
LH刺激thecal cell

單獨添加FSH即可促進卵泡生長
FSH抑制granulosa cell之自我衰亡apoptosis,
添加LH對於卵泡生長並無助益

http://molehr.oxfordjournals.org/content/14/2/75.full

Follicular growth and oocyte competence in the in vitro cultured mouse follicle: effects of gonadotrophins and steroids

1. Alison A. Murray1,†, 
2. Anna K.E. Swales1,4,†, 
3. Rowena E. Smith1,
4. Michael D. Molinek1, 
5. Stephen G. Hillier2 and 
6. Norah Spears1,3

+Author Affiliations

1. ¹Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
2. ²Centre for Reproductive Biology, Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4JT, UK

1. 3Correspondence address. Tel: +44-131-650-3267; Fax: +44-131-651-1706; E-mail: norah.spears@ed.ac.uk

• Received August 6, 2007.
• Revision received September 21, 2007.
• Accepted September 27, 2007.

 

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Abstract

Although there have been extensive studies on the effects of gonadotrophins and steroids on follicular development, less is known as to the effects these hormones have on the acquisition of oocyte developmental competence. This study investigates the effect of altering the gonadotrophin or steroidal environment on follicular development and on oocyte viability and DNA methylation. Oocytes were obtained from pre-ovulatory follicles after individual follicle culture from the pre-antral stage; gonadotrophin or steroid levels were manipulated during the culture period. Oocytes obtained from follicles grown in gonadotrophin free conditions were able to fertilize and develop to the blastocyst stage despite their impaired follicle development. There was no effect of luteinizing hormone or steroids on follicular growth. Altering the steroidal environment did, however, affect oocyte development. The oocytes of follicles exposed to high estrogen levels had lower fertilization rates, regardless of the presence or absence of high androgen levels. The combined presence of high levels of both steroids altered the level of global methylation. This study demonstrates that gonadotrophins and steroids influence the acquisition of developmental competence of the oocyte and suggests that optimal steroid exposure during follicle development is required for the oocyte to mature correctly.

Figure 1:

Growth rates of follicles exposed to different gonadotrophin environments

Values are mean ± SEM (n ≥ 16 for each group). Arrow indicates the start of antral formation in all gonadotrophin groups

Figure 2:

Confocal micrographs after labeling with TUNEL (green) and propidium iodide (red)

Green cells indicate apoptosis. Representative follicles are shown for (A) Gn free, (B) FSH alone, (C) FSH + low LH, (D) FSH + high LH. The follicle grown in Gn free conditions (A) shows a high degree of apoptotic labeling. Scale bar represents 50 µm

Figure 4:

Percentage of oocytes from follicles grown in different gonadotrophin conditions (A) fertilizing and reaching the 2-cell stage and (B) 2-cell embryos developing to the blastocyst stage

Figure 7:

Percentage of oocytes from follicles grown in different steroid environments (A) fertilizing and reaching the 2-cell stage and (B) 2-cell embryos developing to the blastocyst stage. *P < 0.01 compared to control