Compensatory mechanism of the injured lymphatic system: New insights from fluorescent nanoparticle assisted lymphangiography.

Dysfunction of lymphatic system is closely associated with many diseases, including obesity, diabetes, asthma and cancer. During the diagnosis and treatment of lymph related diseases, a deep understanding of the lymphatic morphology and function is of vital importance. Although the tracing of sentinel lymph node is largely achieved in recent years, there is still a lack of systematic depictions of lymphatic drainage pathways, especially in real-time way. This study aims to perform lymphangiography on small animals using FITC@SiO2 nanoparticles (NPs) to systematically depict their lymphatic drainage maps with/without lymphatic injury. FITC@SiO₂ NPs effectively traced lymph nodes and dynamically visualized lymphatic drainage. FITC@SiO₂ NPs enabled the simultaneous observation of blood vessels and lymphatic vessels in vivo. When lymphatic system was damaged, the organism maintained normal lymphatic drainage function by integrating other backup routes or activating the compensatory drainage pathway. In addition, the lymphatic damage leaded to the adaptive remodelling of drainage pathway. This phenomenon might be related to the activation of previously quiescent lymphatic vessels, thereby relieving the hydrostatic pressure caused by the obstruction of lymphatic drainage. Our results indicated that fluorescent colloids hold great potential in the diagnosis and treatment of diseases related to lymphatic system.