Kinoshita Sakiko, Kawauchi Satoko, Nagamatsu Takeshi, Nishidate Izumi, Fujii Tomoyuki, Sato Shunichi
Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
Division of Biomedical Information Sciences, National Defense Medical College Research Institute, Saitama, Japan.
Reprod Sci. 2020 Jan;27(1):172-181. doi: 10.1007/s43032-019-00020-9. Epub 2020 Jan 1.
Obstetric management to prevent hypoxic ischemic encephalopathy (HIE) during labor is important to reduce the cerebral palsy incidence in neonates. A novel approach to monitor or predict fetal brain damage during labor is required. Diffuse reflectance spectroscopy is a noninvasive method routinely used to assess the intrinsic characteristics of tissues. This study investigated the time course of diffuse reflectance signals during an early stage of cerebral cortical damage in a neonatal rat HIE model (Vannucci's model). In the model, an HIE lesion was induced by hypoxic exposure following ligation of the left common carotid artery. Using this model, we established an experimental system to detect diffuse light reflectance signals at time points of interest. Quantitative monitoring of total hemoglobin, oxygen saturation, and scattering amplitude was conducted to examine the basis of the diffused reflectance signals. During hypoxic exposure, which induced HIE damage in the left hemisphere after ligation, the oxygen saturation level decreased, but the difference between the two hemispheres was relatively small. During this period, total hemoglobin was increased in both hemispheres, but the change in the left hemisphere was significantly greater than that in the right, which is attributable to a vigorous compensation response. During hypoxia, scattering amplitude, which reflects cellular/subcellular morphology, revealed a remarkable difference between the two hemispheres. We confirmed that scattering amplitude levels negatively correlated with the extent of edema. These findings suggest that simultaneous monitoring of the scattering amplitude, in addition to hemodynamic parameters, is useful for detecting brain tissue alterations leading to HIE.
在分娩期间采取产科管理措施以预防缺氧缺血性脑病（HIE）对于降低新生儿脑瘫发病率至关重要。需要一种新的方法来监测或预测分娩期间的胎儿脑损伤。漫反射光谱法是一种常用于评估组织内在特征的非侵入性方法。本研究调查了新生大鼠HIE模型（Vannucci模型）中脑皮质损伤早期漫反射信号的时间进程。在该模型中，通过结扎左颈总动脉后进行缺氧暴露诱导HIE损伤。利用该模型，我们建立了一个实验系统，以在感兴趣的时间点检测漫反射光信号。对总血红蛋白、血氧饱和度和散射幅度进行定量监测，以检查漫反射信号的基础。在结扎后导致左半球HIE损伤的缺氧暴露期间，血氧饱和度水平下降，但两个半球之间的差异相对较小。在此期间，两个半球的总血红蛋白均增加，但左半球的变化明显大于右半球，这归因于强烈的代偿反应。在缺氧期间，反映细胞/亚细胞形态的散射幅度在两个半球之间显示出显著差异。我们证实散射幅度水平与水肿程度呈负相关。这些发现表明，除血流动力学参数外，同时监测散射幅度有助于检测导致HIE的脑组织改变。
