Stress Inference in Retinal Pigment Epithelium in C57BL/6J Mouse.

Purpose: To quantitatively map the spatial architecture of mechanical stress and pressure in the retinal pigment epithelium (RPE) and to test the central hypothesis that the mechanical state of normal mouse RPE is spatially patterned from center to periphery and that this spatial pattern is maintained during adult aging. Methods: Whole-mount flat images of C57BL/6J mouse RPE spanning multiple age groups were analyzed using a tissue-scale stress inference framework under the assumption of mechanical equilibrium. Individual RPE cells were segmented, intercellular junctions were skeletonized, and the resulting geometric networks were used to estimate local intracellular pressure and junctional tension. Radial profiles of these mechanical fields were computed from the tissue center to the periphery and systematically compared across age groups. Results: Inferred intracellular pressure exhibited a robust and monotonic decrease from the central to peripheral RPE across all age groups, whereas junctional tension displayed no consistent radial dependence. We did not detect substantial age-associated changes in the inferred pressure and tension profiles among the usable flatmounts analyzed, consistent with apparent preservation of the large-scale mechanical organization across the ages examined. Conclusions: Tissue stress inference revealed robust spatial patterning in inferred RPE mechanics, characterized by a pronounced decline in inferred intracellular pressure toward the periphery and relatively uniform junctional tension across the tissue. No strong age-associated changes were detected in the inferred mechanical profiles, suggesting that the spatial mechanical signatures of the RPE are largely preserved across the ages studied. Together, these data establish a quantitative biomechanical baseline against which AMD- or genotype-associated remodeling of RPE mechanics can be evaluated.