原核胚胎細胞質月暈現象及核仁數目可有效預測胚胎著床率

以原核胚胎之6項指標可以有效預測胚胎之著床率與懷孕率
6項指標包括:
proximity of the PN, 
orientation of the PN with respect to the polar bodies, 
centring of the two PN, 
cytoplasmic halo, 
number of nucleolar precursor bodies (NPB), 
polarization of the NPB. 
其中影響較明顯為

cytoplasmic halo(細胞質月暈現象), 
number of NPB(原核核仁數目), 


http://humrep.oxfordjournals.org/content/21/1/234.full

Morphological scoring of human pronuclear zygotes for prediction of pregnancy outcome

1. Alfred Senn ¹ , 
2. Françoise Urner, 
3. Alain Chanson, 
4. Marie-Pierre Primi,
5. Daniel Wirthner and 
6. Marc Germond

+Author Affiliations

1. Reproductive Medicine Unit, Department of Gynecology and Obstetrics, CHUV, 1011 Lausanne, Switzerland

1. 1To whom correspondence should be addressed at: Fondation F.A.B.E.R., Rue de la Vigie 5, 1003 Lausanne, Switzerland. E-mail: Alfred.senn@cpma.ch

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Abstract

BACKGROUND: As embryo selection is not allowed by law in Switzerland, we need a single early scoring system to identify zygotes with high implantation potential and to select zygotes for fresh transfer or cryopreservation. The underlying aim is to maximize the cumulated pregnancy rate while limiting the number of multiple pregnancies. METHODS: In all, 613 fresh and 617 frozen–thawed zygotes were scored for proximity, orientation and centring of the pronuclei, cytoplasmic halo, and number and polarization of the nucleolar precursor bodies. From these individual scores, a cumulated pronuclear score (CPNS) was calculated. Correlation between CPNS and implantation was examined and compared between fresh and frozen–thawed zygotes. The effect of freezing on CPNS was also investigated. RESULTS: CPNS was positively associated with embryo implantation in both fresh and frozen zygotes. With similar CPNS, frozen zygotes presented implantation rates as high as those of fresh zygotes. Nucleolar precursor bodies pattern and cytoplasmic halo appeared as the most important factors predictive of implantation for both types of zygotes, while pronuclei position was specifically relevant for frozen–thawed zygotes. Freezing induced an alteration of most zygote parameters, resulting in a significantly lower CPNS and a lower pregnancy rate. CONCLUSIONS: CPNS may be used as a single prognostic tool for implantation of both fresh and frozen–thawed zygotes. Lower CPNS values of frozen–thawed zygotes may also be indicative of freezing damage to zygotes. Successful implantation of frozen zygotes despite lower CPNS suggests that they may recover after thawing and in vitro culture.

Figure 1.

Examples of zygote scoring. Scores (1, 2 or 3) assigned to each individual parameter are indicated for each zygote. Cumulated pronuclear score is indicated in parentheses. Bar = 10 µm.

Table II.

Scores (mean ± SD) of individual parameters of the cumulated pronuclear score (CPNS) according to clinical pregnancy

	Non-pregnant group	Pregnant group	Pregnancies with all embryos implanted
Fresh zygotes
No. of transferred zygotes (n)	449	163	45
PN proximity	2.57 ± 0.56A	2.63 ± 0.52G	2.51 ± 0.50
PN orientation	1.93 ± 0.79B	2.03 ± 0.76	1.93 ± 0.75
PN centring	2.52 ± 0.57	2.60 ± 0.51	2.60 ± 0.57
Cytoplasmic halo	1.98 ± 0.75a,C	2.35 ± 0.73a,H	2.31 ± 0.76L
NPB polarization	1.76 ± 0.78b,D	1.91 ± 0.76b,I	2.00 ± 0.73M
NPB number	2.24 ± 0.68c,E	2.46 ± 0.58c,J	2.44 ± 0.62N
CPNS	13.02 ± 2.15d,F	14.00 ± 1.74d,K	13.80 ± 1.64
Frozen–thawed zygotes
No. of transferred zygotes (n)	514	103	20
PN proximity	2.17 ± 0.74e,A	2.33 ± 0.73e,G	2.55 ± 0.68
PN orientation	1.79 ± 0.75f,B	1.97 ± 0.78f	2.10 ± 0.85
PN centring	2.48 ± 0.59g	2.63 ± 0.55g	2.70 ± 0.65
Cytoplasmic halo	1.49 ± 0.66h,C	1.69 ± 0.63h,H	1.65 ± 0.74L
NPB polarization	1.26 ± 0.49i,D	1.43 ± 0.60i,I	1.60 ± 0.68M
NPB number	1.84 ± 0.66E	1.95 ± 0.70J	2.05 ± 0.60N
CPNS	11.06 ± 1.86j,F	12.02 ± 2.13j,K	12.65 ± 2.30

• The no. of transferred zygotes (n) was used to calculate the score means in each group.
• ↵Data with the same lower-case superscripts are significantly different (^a,c,d,jP < 0.0001, ^h,iP < 0.005, ^b,e,f,gP < 0.05). Within the same columns, data with the same upper-case superscripts are significantly different (^{A,C–F,H–K}P < 0.0001, ^B,G,LP< 0.005, ^M–NP < 0.05).
• PN = pronuclei; NPB = nucleolar precursor bodies.

Figure 2.

Influence of the individual parameters of the cumulated pronuclear score (CPNS) on implantation rates after fresh transfers. All the transfers of embryos presenting the same score at the zygote stage (1, 2 or 3) were pooled and the corresponding implantation rates were calculated. The numbers of transferred embryos are indicated on the top of each bar. Bars with the same superscripts are significantly different (χ², ^a,b,cP < 0.005, ^dP < 0.05).