ABSTRACT The decline in oocyte quality with maternal age poses significant challenges for fertility and embryonic development. Traditional methods for assessing oocyte quality rely on invasive techniques that limit their applicability. In this study, we present an integrated analytical approach combining single‐cell Raman spectroscopy with advanced chemometric analysis to profile age‐related metabolic changes in mouse oocytes across developmental stages. Our dual‐pronged methodology encompasses: (1) live‐cell Raman profiling of oocytes at different maturation stages coupled with trajectory inference analysis and multivariate curve resolution‐alternating least squares (MCR‐ALS); and (2) high‐resolution spatial Raman mapping of metaphase II oocytes. Trajectory inference analysis revealed developmental asynchrony in aged oocytes, where nuclear maturation proceeds normally while metabolic maturation lags behind. MCR‐ALS and high‐resolution Raman imaging provided quantification and spatial mapping of key biomolecules, including lipids, proteins, and cytochrome c. Particularly striking was the decline in cytochrome c levels in older oocytes, consistent with mitochondrial dysfunction and impaired energy metabolism. This analytical platform establishes a methodological framework for noninvasive metabolic profiling and spatial analysis of single cells with biochemical specificity. This methodology has broader implications for reproductive biology and potential applications in clinical diagnostics and assisted reproductive technologies.
Xiong et al. (Wed,) studied this question.