Evaluation of oocyte quality: morphological, cellular and molecular predictors.
Mounting evidence that oocyte quality profoundly affects fertilisation an d subsequent embryo development drives the continued search for reliable predictors of oocyte developmental competence. In the present review, we provide an overall summary and analysis of potential criteria that can be used to evaluate oocyte quality. These criteria are specifically classified as morphological and cellular/molecular predictors. Traditional methods for the evaluation of oocyte quality are based on morphological classification of thefollicle, cumulus-oocytecomplex, polar body and/or meiotic spindle. Although the use of morphological characteristics as predictors of oocyte quality is controversial, such a grading system can provide valuable information for the preselection of oocytes with higher developmental competence and, therefore, may maximise embryo developmental outcome. Several intrinsic markers (such as mitochondrial status and glucose-6-phosphate dehydrogenase 1 activity) and extrinsic markers (such as apoptosis of follicular cells and levels of the transforming growth factor-beta superfamily in follicular fluid or serum) have also been reported as useful indicators of oocyte competence and embryo quality. Compared with the morphological parameters, these cellular and molecular predictors of oocyte quality may prove to be more precise and objective, although further studies and refinement of techniques are needed.
Wang
Qiang
Q
State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China.
Sun
Qing-Yuan
QY
D000818:Animals; D017209:Apoptosis; D015415:Biomarkers / Q000032:analysis; D047108:Embryonic Development / Q000502:physiology; D005260:Female; D015571:Follicular Fluid / Q000378:metabolism; D020869:Gene Expression Profiling; D006801:Humans; D020738:Leptin / Q000378:metabolism; D009865:Oocytes / Q000166:cytology* / Q000502:physiology*; D010053:Ovary / Q000502:physiology; D027724:Reproductive Techniques, Assisted; D013256:Steroids / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism
D015415:Biomarkers; D020738:Leptin; D013256:Steroids; D016212:Transforming Growth Factor beta