Fig. 4

Histological brain tissue alterations in the cervical lymph node dissection (CLND) group. (a) The merged images between the region of high-water content by measuring THz imaging and fixed tissue in the paraffin block. The structural alterations in brain tissue are primarily investigated around regions with differences in water content: meninges (M), cerebral cortex (CC), and white matter (WM) of the corpus callosum. LV: lateral ventricle, TV: third ventricle. (b) Tissue structure comparisons in each section. In the CLND group, a decrease in peripheral brain tissue density is observed along with meningeal edema. In the cerebral cortex of CLND animals, many apoptotic cells are identified, including considerable tissue density reduction (red arrows). A decrease in the tissue capsule is observed in the WM of CLND animals. These changes are more noticeable at 8 weeks (8 W) than at 2 weeks (2 W). (c) Quantification of the cell nucleus areas in the CC and WM regions of animals in each group. At 8 W, the CLND group shows a significant difference in cell nucleus area compared with the control group (t-test, **p < 0.01 and ***p < 0.001)