Arthritis Induced with Freund's Adjuvant and its Relationship to Changes in the Stomach, Small Intestine and Thymus: A Histological and Tritiated Thymidine Study on Rats.

The aim of the study was to elucidate histological changes provoked by Mycobacterium butyricum toxine in the rat joints, stomach, small intestine and thymus and the uptake of tritiated thymidine. Freund's complete adjuvant was injected into the base of the vastus muscle of 35 rats; 21 rats served as controls. Fifteen rats displayed histologically mild synovitis in the ankle joint, two periostitis and three muscle infiltrates. Histological study revealed no difference between the test animals and the controls in the stomach, small intestine and thymus. The thymidine uptake of the adjacent growth lines of the knee, stomach mucosa, small intestine, spleen and liver was the same in both groups. In contrast, the uptake of the cells of the thymus was smaller in the adjuvant-treated rats with a probability of over 90 per cent. This suggests that the mitosis of adjuvant-induced thymic cells is smaller than in cells with a normal condition.