Computer-Generated Ovaries to Assist Follicle Counting Experiments

Precise estimation of the number of follicles in ovaries is of key importance in the field of reproductive biology, both from a developmental point of view, where follicle numbers are determined at specific time points, as well as from a therapeutic perspective, determining the adverse effects of environmental toxins and cancer chemotherapeutics on the reproductive system. The two main factors affecting follicle number estimates are the sampling method and the variation in follicle numbers within animals of the same strain, due to biological variability. This study aims at assessing the effect of these two factors, when estimating ovarian follicle numbers of neonatal mice. We developed computer algorithms, which generate models of neonatal mouse ovaries (simulated ovaries), with characteristics derived from experimental measurements already available in the published literature. The simulated ovaries are used to reproduce in-silico counting experiments based on unbiased stereological techniques; the proposed approach provides the necessary number of ovaries and sampling frequency to be used in the experiments given a specific biological variability and a desirable degree of accuracy. The simulated ovary is a novel, versatile tool which can be used in the planning phase of experiments to estimate the expected number of animals and workload, ensuring appropriate statistical power of the resulting measurements. Moreover, the idea of the simulated ovary can be applied to other organs made up of large numbers of individual functional units.

卵巢卵泡数量的精准估算在生殖生物学领域具有核心价值：从发育生物学视角来看，卵泡数量于特定时间点确立；从治疗学视角而言，则可用于评估环境毒素与癌症化疗药物对生殖系统的不良影响。影响卵泡数量估算结果的两大核心因素为采样方法，以及同品系动物间因生物学变异（biological variability）导致的卵泡数量差异。本研究旨在评估，在估算新生小鼠卵巢卵泡数量时，上述两大因素所产生的影响。我们开发了计算机算法，可生成基于已发表文献中实验测量参数构建的新生小鼠卵巢模型——模拟卵巢（simulated ovaries）。利用该模拟卵巢开展基于无偏体视学技术（unbiased stereological techniques）的虚拟计数实验；本研究提出的方法可在给定特定生物学变异与预期准确度的前提下，确定实验所需的卵巢样本数量与采样频率。模拟卵巢是一种全新的多功能工具，可用于实验规划阶段，以预估所需实验动物数量与实验工作量，确保后续测量结果具备恰当的统计效力（statistical power）。此外，模拟卵巢的构建思路可推广至其他由大量独立功能单元构成的器官。