基于光学性能检测的高效卵细胞质量评价方法研究

Evaluation of oocyte quality is crucial for the assisted reproductive technology, which is the key factor for oocyte fertilization, embryo development, clinical pregnancy and newborn health. However, there is still a lack of an objective, accurate and effective method to evaluate oocyte quality. It has been found that the changes of oocyte microstructures during the processes of development or lesion would affect the optical properties. Thus, this project plans to detect the optical properties (polarization, spectrum and intensity) of oocytes to build a novel method for noninvasive and efficient evaluation of oocyte quality. This project will take in-vitro cultured mouse oocytes as experiment samples, and study the dynamic variations in the optical properties of zona pellucida, cytoplasm and other biological structures during the processes of the normal development, in-vitro aging and development mutation. This project will combine full-field optical coherence tomography (OCT) and Muller matrix to comprehensively analyze the polarization characteristics of oocytes. The full-field OCT and Fourier analysis will be used to study the back-scattering spectra of oocytes in the way of the union of imaging and spectrum. The back-scattering intensities of oocytes will be characterized by estimating the gray distributions of the OCT images of oocytes and the features of the corresponding frequency-domain images. This project provides a new research idea to evaluate oocyte quality objectively, accurately and efficiently.

卵细胞质量评价对辅助生殖技术至关重要，它是决定卵细胞受精、胚胎发育、临床妊娠及新生儿健康与否的关键因素。然而目前仍欠缺客观、准确、高效地评价卵细胞质量的方法。已有研究发现，卵细胞在发育或病变过程中，其微观结构将发生变化，引起光学性能改变。因此，本项目拟基于卵细胞的光学性能（偏振、光谱及强度）检测，建立一套全新的无损高效评价卵细胞质量的方法。本项目以体外培养的小鼠卵细胞为实验对象，拟研究其在正常发育、体外老化及发育异变过程中透明带、胞质等生物结构的光学性能的动态变化。本项目拟结合全场光学相干层析（OCT）及Mueller矩阵技术，全面解析卵细胞的偏振特性。拟结合全场OCT与傅里叶分析技术，以“图谱合一”的方式，研究卵细胞的背向散射光谱特性。拟通过卵细胞OCT图像的灰度分布及频谱图像特征分析卵细胞背向散射强度特点。本项目为客观、准确、高效评估卵细胞质量提供了全新的研究思路。

卵母细胞作为雌性动物特有的生殖细胞，在生物与医学领域具有巨大的研究及应用价值，卵母细胞的质量显著地影响着体外受精及胚胎移植的成功率，从而影响人类的辅助生殖、动物的育种、品种改良及保存濒危物种等工作。然而，目前仍缺乏恰当的评估卵母细胞质量的方法。本项目通过检测卵母细胞的光学性能来无损、高效地评估卵母细胞的质量。具体地，我们对不同发育时期，不同发育质量的卵母细胞进行了偏振、光谱及散射强度等光学性质检测。结果显示，卵母细胞的偏振特性会随着其不同生理状态而变化，特别是偏振度和线性相位延迟两个偏振参数，可以很好地反映未成熟卵母细胞、排卵后老化的卵母细胞及药物诱导质量下降的卵母细胞与新鲜成熟卵母细胞之间的差别。卵母细胞的光谱特性也与其发育及质量紧密相关。与新鲜成熟的卵母细胞相比，未成熟及排卵后老化的卵母细胞的光谱主要在深紫外波段200-250nm、可见光波段420-600nm及近红外波段860-930nm存在差别。可见光波段的差别更易于实际应用，该波段的光谱差别具体为与新鲜成熟的卵母细胞相比，未成熟卵母细胞的胞质、透明带的光谱在451nm和467nm处有差别；排卵后老化卵母细胞的胞质、透明带、极体、卵周间隙的光谱失去了在425nm及571nm处的峰。卵母细胞的散射强度也反映出卵母细胞的质量。研究发现，具有大面积的皮质散射增强区且胞质区散射强度均匀的卵母细胞，具有更优越的发育质量与更强的发育潜能。这些结果充分表明了卵母细胞光学性质检测用于甄别卵母细胞质量的可行性及实用性。本项目的研究内容及结果为卵母细胞质量甄选工作提供了全新的思路，具有明确的科学意义。