Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, People's Republic of China.
PLoS One. 2012;7(5):e37962. doi: 10.1371/journal.pone.0037962. Epub 2012 May 24.
Pancreatic cancer is a lethal disease with a 5-year survival rate of only 1-5%. The acceleration of intraoperative histological examination would be beneficial for better management of pancreatic cancer, suggesting an improved survival. Nonlinear optical methods based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) of intrinsic optical biomarkers show the ability to visualize the morphology of fresh tissues associated with histology, which is promising for real-time intraoperative evaluation of pancreatic cancer.
METHODOLOGY/PRINCIPAL FINDINGS: In order to investigate whether the nonlinear optical imaging methods have the ability to characterize pancreatic histology at cellular resolution, we studied different types of pancreatic tissues by using label-free TPEF and SHG. Compared with other routine methods for the preparation of specimens, fresh tissues without processing were found to be most suitable for nonlinear optical imaging of pancreatic tissues. The detailed morphology of the normal rat pancreas was observed and related with the standard histological images. Comparatively speaking, the preliminary images of a small number of chemical-induced pancreatic cancer tissues showed visible neoplastic differences in the morphology of cells and extracellular matrix. The subcutaneous pancreatic tumor xenografts were further observed using the nonlinear optical microscopy, showing that most cells are leucocytes at 5 days after implantation, the tumor cells begin to proliferate at 10 days after implantation, and the extracellular collagen fibers become disordered as the xenografts grow.
CONCLUSIONS/SIGNIFICANCE: In this study, nonlinear optical imaging was used to characterize the morphological details of fresh pancreatic tissues for the first time. We demonstrate that it is possible to provide real-time histological evaluation of pancreatic cancer by the nonlinear optical methods, which present an opportunity for the characterization of the progress of spontaneous pancreatic cancer and further application in a non-invasive manner.
胰腺癌是一种致命疾病，5 年生存率仅为 1-5%。加速术中组织学检查将有利于更好地管理胰腺癌，提示生存改善。基于双光子激发荧光（TPEF）和固有光学生物标志物的二次谐波产生（SHG）的非线性光学方法显示出可视化与组织学相关的新鲜组织形态的能力，这对于实时评估胰腺癌具有很大的应用前景。
方法/主要发现：为了研究非线性光学成像方法是否具有以细胞分辨率表征胰腺组织学的能力，我们使用无标记 TPEF 和 SHG 研究了不同类型的胰腺组织。与其他用于制备标本的常规方法相比，发现未经处理的新鲜组织最适合用于胰腺组织的非线性光学成像。观察了正常大鼠胰腺的详细形态，并与标准组织学图像相关联。相比之下，少量化学诱导的胰腺癌组织的初步图像显示出细胞和细胞外基质形态上可见的肿瘤差异。进一步使用非线性光学显微镜观察皮下胰腺肿瘤异种移植物，结果显示，植入后 5 天大多数细胞为白细胞，植入后 10 天肿瘤细胞开始增殖，随着异种移植物的生长，细胞外胶原纤维变得紊乱。
结论/意义：在这项研究中，首次使用非线性光学成像来描述新鲜胰腺组织的形态细节。我们证明，通过非线性光学方法可以实时评估胰腺癌的组织学特征，这为自发性胰腺癌的进展提供了特征描述的机会，并进一步以非侵入性的方式进行应用。
