Macroscopic polarimetric discrimination and quantification of antiangiogenic effect of AGRO aptamer and GK1 peptide in a preclinical melanoma model.

Histological analysis remains the gold standard for tissue diagnosis and evaluation, but it often relies on subjective visual interpretation and limited field of view areas. In this study, we present a macroscopic, wide-field Mueller polarimetric imaging approach for the quantitative analysis of histological sections of melanoma induced with the B16F10 cell line in mice. By using the depolarization index, our method enables objective tissue discrimination based on intrinsic tissue properties. A color-coded segmentation mask derived from the depolarization index values was implemented to classify tissue into strongly depolarizing regions, associated with blood vessels, and weakly depolarizing regions, which predominantly correspond to tumor cell-dominated tissue. This pixel-wise classification allowed for quantitative mapping and statistical analysis of spatial heterogeneity across several mm² of entire histological sections, significantly extending the field of view compared to conventional microscopy. As a potential application, the technique was applied to evaluate histological sections from a preclinical murine melanoma model subjected to a treatment regimen including antiangiogenic agents. The results demonstrated measurable differences in the amount of strongly depolarizing tissue, associated with blood vessels, in the treatment group, supporting the method's sensitivity to antiangiogenic effects in the tumor microenvironment. These findings highlight the potential of Mueller polarimetry as a complementary tool for histological assessment, enabling reproducible, large-area tissue characterization beyond visual inspection.