Mouse oocyte phenotypes differ in blastocyst response to resveratrol and vitamin B12

Abstract

This experimental laboratory study examined whether associations between culture condition and blastocyst formation differed across radiomics-defined oocyte clusters and age groups. Mouse oocytes (n = 2,061) were assigned to control or five supplementation groups: resveratrol (0.1, 0.5, 1.0 μM) and vitamin B12 (50, 200 pM). The primary outcome was blastocyst formation across morphological clusters and age subgroups. Three clusters with distinct baseline blastocyst formation rates were identified: Cluster 1, 28.2% (44/156); Cluster 2, 42.4% (156/368); and Cluster 3, 34.9% (105/301). Cluster 2 comprised the largest and most spherical oocytes with heterogeneous cytoplasmic texture. Cluster 3 represented the smallest, brightest phenotype with the most uniform intensity profile, whereas Cluster 1 showed intermediate size, irregular contours, and high internal contrast. Associations between culture condition and blastocyst formation differed across radiomics-defined clusters. In Cluster 1, blastocyst formation increased from 28.2 to 45.1% with resveratrol 1.0 μM and to 48.7% with vitamin B12 200 pM. In Cluster 3, blastocyst formation increased from 34.9 to 60.4% with vitamin B12 50 pM and to 50.0% with resveratrol 0.1 μM. Cluster 2 showed a non-significant increase from 42.4 to 57.9% with resveratrol 0.5 μM. Older oocytes exhibited lower developmental competence than younger oocytes. Selecting the best performing medium for each cluster–age combination increased overall blastocyst formation from 36.97% (305/825) to 56.00% (126/225). These findings indicate associations among radiomics-defined clusters, culture conditions, and blastocyst formation. Prospective cluster-stratified studies are required to determine whether cluster-guided culture-condition selection improves developmental outcomes.

Lay summary

Not all eggs have the same ability to develop into embryos, and they may respond differently to the conditions in which they are cultured. In this study, we analysed images of more than 2,000 mouse eggs to determine whether features visible in the images could identify groups of eggs with different developmental potential. We first used eggs grown under standard culture conditions to define three groups based on their image characteristics. We then examined how eggs in these groups developed under standard conditions or with different amounts of resveratrol, an antioxidant, or vitamin B12 added to the special fluid used to support embryo development. The three groups differed in their rates of development to the blastocyst stage, an early stage of embryo development, and the relationship between culture condition and blastocyst development also varied between groups and between younger and older mice. These findings suggest that egg image characteristics may help us understand why eggs respond differently to their culture environment. However, further prospective experiments are needed before these findings can be used to guide culture conditions.

Keywords:

radiomics, oocyte morphology, blastocyst formation, resveratrol, vitamin B12