Time-dependency of the lymphatic efflux of intracerebrally applied corpuscular tracers. Light and electron microscopic investigations

Abstract

Morphologic methods were used to investigate the rate at which intracerebrally injected corpuscular tracers (carbon, ferritin, and colloidal gold) appear in the cervical lymph nodes of rabbits. The survival intervals ranged from 3 minutes to 90 days. The lymph nodes were examined with light microscopy and sometimes also with electron microscopy. Ferritin was first detected in the deep paratracheal cervical lymph nodes 6 minutes after injection with electron microscopy and 10 minutes after injection with light microscopy. All tracers appeared first extracellularly in the sinuses of the lymph nodes; within 3 hours, however, they had been almost entirely incorporated, appearing then in the sinus lining cells as well as in the lymph node macrophages. In the following days, the tracer concentrated and accumulated in the macrophages. After 12 days, all tracer-bearing macrophages had already disappeared. The amount and distribution of tracer in the sinus lining cells, however, remained virtually unchanged during the entire 3-month observation period. The importance of these observations is discussed.