Isolation and Characterization of Exosomes Derived from Mouse Spleen Tissues

Exosomes (Exo) are lipid-bilayer structures secreted by various cells, including those of animals, plants, and prokaryotes. Previous studies have revealed that Exo derived from humoral or cell-supernatant are promising targets for novel diagnostic or prognostic biomarkers, underscoring their significant role in disease pathogenesis. Tissue-derived Exo (Ti-Exo) have attracted increasing attention due to its ability to accurately reflect tissue specificity and the microenvironment. Ti-Exo, present in interstitial space, play crucial roles in intercellular communication and cross-organ signaling. Despite their recognized value in elucidating disease mechanisms, isolating Ti-Exo remains challenging due to the complexity of tissue matrices and variability in extraction methods. In this study, we developed a practical protocol for isolating exosomes from mice spleen tissue, providing a reproducible technique for subsequent identification analysis and functional studies. We used Type I collagenase digestion combined with differential ultracentrifugation to isolate spleen-derived Exo. The characteristics of isolated Exo were determined through electron microscopy, the nano-flow cytometer, and the western blot. The isolated spleen-derived Exo displayed the typical morphology of lipid bilayer vesicles, with particle sizes ranging from 30 nm to 150 nm. In addition, the expression profile of exosome markers confirmed the presence and purity of exosomes. Taken together, we successfully established a practical protocol for isolating spleen-derived Exo in mice.