The cervix is a collagen-rich connective tissue that must remain closed during pregnancy while undergoing progressive remodeling in preparation for delivery, which begins before the onset of the preterm labor process. Therefore, it is important to resolve the changes of collagen fibers during cervical remodeling for the prevention of preterm labor. Herein, we assessed the spatial organization of collagen fibers in a three-dimensional (3D) context within cervical tissues of mice on day 3, 9, 12, 15 and 18 of gestation. We found that the 3D directional variance, a novel metric of alignment, was higher on day 9 than that on day 3 and then gradually decreased from day 9 to day 18. Compared with two-dimensional (2D) approach, a higher sensitivity was achieved from 3D analysis, highlighting the importance of truly 3D quantification. Moreover, the depth-dependent variation of 3D directional variance was investigated. By combining multiple 3D directional variance-derived metrics, a high level of classification accuracy was acquired in distinguishing different periods of pregnancy. These results demonstrate that 3D directional variance is sensitive to remodeling of collagen fibers within cervical tissues, shedding new light on highly-sensitive, early detection of preterm birth (PTB).

The tumor microenvironment (TME) is now recognized as an important participant of tumor progression. As the most abundant extracellular matrix component in TME, collagen plays an important role in tumor development. The imaging study of collagen morphological feature in TME is of great significance for understanding the state of tumor. Multiphoton microscopy (MPM), based on second harmonic generation (SHG) and two-photon excitation fluorescence (TPEF), can be used to monitor the morphological changes of biological tissues without labeling. In this study, we used MPM for large-scale imaging of early invasive breast cancer from the tumor center to normal tissues far from the tumor. We found that there were significant differences in collagen morphology between breast cancer tumor boundary, near tumor transition region and normal tissues far from the tumor. Furthermore, the morphological feature of eight collagen fibers was extracted to quantify the variation trend of collagen in three regions. These results may provide a new perspective for the optimal negative margin width of breast-conserving surgery and the understanding of tumor metastasis.

福尔马林溶液对于固化关节软骨组织、 防止在长时间测量过程中组织的分解退化起到很好的作用, 但对福尔马林溶液浸泡后软骨组织的结构变化(固化)过程及其胶原纤维各向异性的改变却鲜有研究。 采用傅里叶变换红外光谱显微成像技术与偏振技术相结合的方法, 通过关节软骨内胶原纤维(蛋白)的红外光谱特征吸收峰(Amide Ⅰ, Amide Ⅱ带)的吸光度随福尔马林溶液浸泡时间及偏光角度的变化来研究福尔马林溶液对软骨组织结构即胶原纤维各向异性的影响, 并利用与各向异性方程拟合得到的决定系数(R2)对胶原蛋白纤维各向异性程度进行表征。 研究发现, 关节软骨Amide Ⅰ和Amide Ⅱ带的各向异性随着福尔马林浸泡时间的增长而愈加明显(Amide Ⅰ带变化尤为明显), 说明福尔马林溶液中甲醛分子诱发了胶原蛋白分子新的交联, 最终获得较好的固化效果, 有利于关节软骨的各向异性分析。 本研究将为今后关节软骨样本的制备、 储存及各向异性研究提供参考。

胶原质丰富而且结构排列整齐的生物组织受光照射时会显示双折射的特性.通过精确地控制入射光和反射光的偏振状态,偏振光学相干层析技术能够显示出组织的双折射性.我们利用斯托克斯参数和琼斯矢量,着重讨论点光源照射样品后其背景反射光的偏振特性,从而导出组织的偏振特性.