[Distribution of a diffusible tracer in the subcapsular sinus and the cortex of lymph nodes in the rat].

Abstract

The observations of a previous work on the architecture of the rat node suggested that the organ is divided into "physiological compartments". Each compartment corresponds to a node portion stimulated by the immunogenic content poured by an opening of an afferent lymphatic or a branch of it. The same study also investigated the lymph flow in the organ sinuses by analysing the distribution, in draining nodes, of a locally injected small dose of China ink. It was found that the ink, pouring into a node from a lymphatic opening, had spread in a restricted portion of its subcapsular sinus corresponding to that of a compartment. The finding thus supported the proposal on the physiological compartmentation of the organ. However, the question arose as to whether such restricted ink distribution in the sinus did not result from the non-diffusible and unphysiological nature of the ink. We, therefore, repeated the latter analysis with a diffusible and physiological tracer: uridine-3H. The similarity of the results of the latter analysis, with those of the preceeding one, indicate that the observations witness the physiological modalities of the pattern of lymph flow in the organ sinuses. It, therefore, confirms that the node is divided into physiological compartments. Additional observations of present work, further demonstrate that small sized lymph substances diffuse from the subcapsular sinus into the cortex. The process is maximal under a lymphatic opening and decreases along the sinus with distance from the opening.