OIL-INDUCED ARTHRITIS IN DA RATS - TISSUE DISTRIBUTION OF ARTHRITOGENIC C-14-LABELED HEXADECANE

As part of the study of the pathogenesis of oil-induced arthritis in D A rats, the tissue dissemination of arthritogenic oil labelled with C- 14 has been determined. Rats received labelled hexadecane in arthritog enic doses by the intradermal route and were killed at 1 and 6 h, 2, 1 0, 14, 18 and 27 days after injection. Whole-body autoradiography was performed and localization of radioactivity in different organs was in vestigated. With the exception of the injection site, the lymph nodes showed the highest content of radioactivity throughout the study. Radi oactivity could be seen in the popliteal, inguinal and axillary lymph nodes. Detailed examination of lymph nodes revealed at 1 h radioactivi ty in the subcapsular sinus of the lymph node. By 10 days the activity had spread to the cortex and paracortex, apart from the subcapsular s inus. The activity in other lymphoid organs, such as the bone marrow a nd spleen, was more transient, with a peak at 2 days. Oil disseminatin g to joints was not prominent: very little radioactivity was observed in the knee joints of both non-arthritic and arthritic animals. From t hese data it is suggested that the adjuvant oil exerts its major proar thritogenic activity in the lymph nodes rather than directly in the jo ints.