Morphologic indicators predict the stage of chromatin condensation of human germinal vesicle oocytes recovered from stimulated cycles

Abstract

Objective: To assess germinal vesicles (GV) recovered from stimulated cycles by means of morphometric and morphologic examination (using contrast-phase and image analysis) and chromatin configuration (using fluorescent DNA imaging), and to evaluate the relevance of morphometric and morphologic parameters as forecasters of chromatin status.

Design: Experimental study.

Setting: University-affiliated infertility clinic.

Patient(s): One hundred and thirty-one GV oocytes donated to patients for intracytoplasmic sperm injection.

Intervention(s): We evaluated 131 GVs by means of morphology and morphometry with the use of contrast phase microscopy. They were subsequently fixed, DNA stained, and assessed by fluorescent microscopy. Compiled data were retrospectively grouped according to three models.

Main outcome measure(s): Model A: ova were grouped according to chromatin condensation (noncondensed vs. condensed). Model B: ova were grouped according to chromatin distribution in relation to the nucleolus-like body (NLB) (not surrounding vs. surrounding and/or absent) but regardless of the condensation stage. Model C: GV oocytes were grouped according to the combination of both of the previously mentioned parameters (chromatin condensation and distribution in relation to the NLB).

Result(s): According to the GV classification of model A, nucleoplasm, nucleus position, nuclear envelope continuity, and oocyte size were shown to be relevant and were included in a mathematical model for predicting chromatin condensation stage.

Conclusion(s): Noninvasive analysis of GV oocytes using contrast-phase microscopy maintains oocytes in a viable state and allows the chromatin condensation status to be predicted.