Spleen and lymph node reticulofibrosis in "chemically thyroidectomized" rats

The effects of the X-rays on the peripherial lymphoid organs (lymph nodes and spleen) in male adult wistar rats "chemically thyroidectomized" (methylthiouracil) have been studied. Spontaneous death of these animals 9 days after the irradiation was determined by the hypoplasia (aplasia) of the hematogenous bone marrow. The spleen and lymph node changes -- represented by the lymphoid tissue depletion and reticulofibrosis -- in the experimental animals were similar to those observed in animals sacrificed 6-8 months after irradiation. They differed from the latter by the absence of the macromolecular hyperstability of the reticular and collagenous fibers, which is proper to early ageing by X-rays.