A Mouse Model of Endometriosis Using Ex Vivo Cy5.5 Dye-Doped Silica Nanoparticle Labeling for Lesion Visualization

Endometriosis is a common gynecological disorder characterized by the growth of endometrial-like tissue outside the uterine cavity, leading to chronic inflammation, pelvic pain, and infertility. Reliable mouse models are essential for investigating the molecular, hormonal, immune, and environmental mechanisms underlying disease development and progression. Conventional methods for identifying endometriotic lesions often rely on genetically engineered fluorescent reporter mice, which are time-consuming and costly to generate. Here, we present a simple, non-genetic approach to inducing and visualizing endometriosis in mice by ex vivo labeling donor uterine tissue fragments with Cy5.5-doped silica nanoparticles prior to transplantation. The nanoparticles exhibit favorable physicochemical properties, high fluorescence stability, and minimal cytotoxicity, enabling efficient labeling of uterine tissue without compromising experimental procedures. Following intraperitoneal implantation into recipient mice, Cy5.5-labeled endometriotic lesions can be readily distinguished from surrounding host tissues using fluorescence imaging. This protocol provides a reproducible and versatile method for lesion visualization and tracking, facilitating studies of endometriosis pathogenesis and the preclinical evaluation of diagnostic and therapeutic strategies without the need for genetic manipulation.