Abstract
Morphological changes of the fine structures in the submandibular lymph nodes, such as the afferent and effercnt lymphatic vessels and the marginal sinuses, were studied by the scanning electron microscope after the inoculation of the lipopolysaccaride into the periodontal tissues of the mouse (ICR strain). The histopathological observations and the immunopathological observations of immunoglobulin G (IgG) using the fluorescent antibody technique were also performed. Results obtained were as follows. 1. The afferent lymphatic vessels were observed at many places over the convex surface neibouring the marginal sinuses of the submandibular lymph nodes. The bundled efferent lymphatic vessels were seen in their hilus. 2. At one day after the inoculation, it was pathologically found that the infiltrations of the numberous granulocytes in the outer cortex and the sinuse. In the immunopathological observations, it was recognized that two distinct types of IgG positive cells were scattered in the marginal sinuses and the outer cortex. The lots of IgG positive cells also appeared in the deep cortex and the intermediate sinuses. 3. At three or five days after the inoculation, the lymph nodes showed the pathological changes, such as the broadness of the deep cortex, the indistinctness of the border between the deep cortex and the outer one, the disappearences of the germinal centers and the reduction of the medulla sinuses. The plasma cells and the monocytes markedly infiltrated in the deep cortex and the sinuses. In the immunopathological observations, it was shown that free IgG and the lots of IgG positive cells were spreaded in the deep cortex and the sinuses and also localized in the medulla and the medulla sinuses. 4. At seven days after the inoculation the nodes seemed to be recovering to the normal state, as the shapes of the deep cortex, the medulla and the medulla sinuses showed their distinct anatomical characters. In the immunological observations, it was shown that the small masses of the fluorescent of the IgG positive cells were scattered in the outer cortex and the deep cortex and were also widely observed in the medulla. 5. Free IgG and the IgG positive cells seemed to occur in the deep cortex and in the sinuses in the early periods of the inoculation, and gradually move to the medulla sinuses in the course of the time.
