中空透明帶內層厚度較厚與折光度較高之胚胎品質較佳

2PN胚胎中空透明帶(ZP)之內層厚度較厚與折光度較高之胚胎品質較佳

使用polescopy觀查2PN胚胎正常中空透明帶(ZP)的3層結構:
OL: 外層, 灰
ML: 中層, 黑
IL: 內層, 白, 亮

http://humrep.oxfordjournals.org/content/20/6/1596.full



High magnitude of light retardation by the zona pellucida is associated with conception cycles

1. Y. Shen1,2, 
2. T. Stalf1, 
3. C. Mehnert1, 
4. U. Eichenlaub-Ritter3,4 and
5. H.-R. Tinneberg1,2

+Author Affiliations

1. ¹Centre of In-Vitro-Fertilisation (CIF) in the Justus-Liebig-University, ²Department of Gynaecology and Obstetrics, Women's Hospital, Justus-Liebig-University Giessen, D-35392 Giessen and ³University of Bielefeld, Faculty of Biology IX, Gene Technology/Microbiology, D-33501 Bielefeld, Germany

1. 4To whom correspondence should be addressed. Email: EiRi@uni-bielefeld.de

• Received September 9, 2004.
• Revision received January 14, 2005.
• Accepted January 21, 2005.

Next Section

Abstract

BACKGROUND: Failures in expression of zona proteins correlate to subfertility in animals. Low expression of the zona proteins by the growing human oocyte may indicate reduced developmental potential. Therefore, we non-invasively analysed the thickness and the structure of the zona pellucida (ZP) of human oocytes with respect to embryo fate after ICSI. METHODS: Retardance magnitude and thickness of the inner, middle and outer layers of the ZP were quantitatively analysed by a Polscope in 166 oocytes selected for transfer after ICSI (63 patients; 32.8±4.4 years) on the basis of pronuclear score at day 1. Blastomere number was determined at day 2. Data were compared between conception cycles (CC; 65 oocytes/23 patients) and non-conception cycles (NCC; 101 oocytes/40 patients) and with respect to maternal age. RESULTS: The thickness was slightly elevated (P<0.001), and the mean magnitude of light retardance was nearly 30% higher (P<0.001) in the inner layer of the zona pellucida of oocytes contributing to CC compared to NCC. Embryos in the CC group tended to develop faster. CONCLUSIONS: The magnitude of light retardance by the zona pellucida inner layer appears to present a unique non-invasive marker for oocyte developmental potential.

Figure 1.

Images of human oocytes selected for embryo transfer. (A) The zona pellucida of oocytes observed by light microscopy appears transparent. (B) The three-laminar architecture of zona pellucida with a highly birefringent inner layer (IL), followed by a dark-appearing middle layer (ML, arrow) and a greyish-appearing outer layer (OL) can be detected by Polscope microscopy. (C) Most oocytes of the conception cycle (CC) group contained a bright and thick zona pellucida. (D) Measurements of the thickness and retardance magnitude of the zona pellucida in each individual oocyte were done in three areas. The first and second measurements were done on a cross-sectional region of the zona on a line scan through the centre of the oocyte (dotted line). The third line scan was perpendicular to the two first measurements at an angle of ∼90°. (D–F) Oocytes from patients in the non-pregnant group with aberrant zona pellucida, which was either relatively thin (D), irregular (E) or sub-split into two layers (F, arrows). (G) Typical retardance curve of a line scan through the zona pellucida of an oocyte from the CC group (solid line) and the non-conception cycle (NCC) group (dotted line) respectively. Vertical dotted lines depict outer boundaries of layers measured on the line scan of the oocyte contributing to a CC or NCC. Open arrows show the outer measurement points included in the calculation of the magnitude of retardance of the outer and inner layers. For the middle layer, calculation was from the boundaries defined by the dotted vertical lines. (H) Scheme of the thickness, and retardance magnitude of the three zona layers in CC versus NCC. RT = retardance. Bar = 25 μm.

Table II.

Mean retardance magnitude and thickness of the individual zona layers as assessed by Polscope microscopy in oocytes contributing to conception cycle (CC) and non-conception cycle (NCC) groups

	CC (transferred)	NCC (transferred)
No. of patients	23	40
No. of oocytes	65	101
Zona inner layer (mean ± SD)
Retardance (nm)	2.81±0.60a	2.15±0.41
Thickness (μm)	11.25±1.44a	9.36±1.74
Zona middle layer (mean±SD)
Retardance (nm)	0.35±0.08	0.35±0.07
Thickness (μm)	3.92±0.76	3.66±0.65
Zona outer layer (mean±SD)
Retardance (nm)	0.55±0.18	0.55±0.14
Thickness (μm)	4.80±1.40	5.55±1.03
Zona total thickness (mean±SD) (μm)	19.87±1.92b	18.58±1.82

• ^a,bSignificantly different from the NCC group: ^aP≤0.001, ^bP≤0.01 (t-test).

Figure 2.

Pronuclear scoring system (modified from Scott and Smith, 1998). (A–D) Score A–D: pronuclei closely apposed, further designation according to the position of nucleoli as follows: (A) Score A: three to 10 nucleoli aligned at the pronuclear junction. (B) Score B: nucleoli polarized but not highly apposed at pronuclear junction. (C) Score C: More than seven nucleoli scattered in nucleoplasm. (D) Score D: asymmetric distribution of nucleoli and/or numbers of nucleoli >10 or <5. (E) Score E: pronuclei spatially separated, unequal in size and/or not clearly distinguishable.