HISTOCHEMICAL AND AUTORADIOGRAPHIC STUDY OF OSTEOLATHYRISM IN SKELETAL AND PERIODONTAL TISSUES

Abstract

Osteolathyrism experimentally induced in weanling rats was observed morphologically, enzymatic histochemically and 3H-thymidine autoradiographically in the skeletal and periodontal tissues.Morphological changes in the epiphyseal plate were an elongation of the plate and disarrangement of the cartilage cells, especially of the hypertrophic cartilage cell layer in the primary stage, and a shortening of the epiphyseal plate in the advanced stage. Histochemical activities for hydrolytic and oxidative enzymes were rather decreasing, but varying in the primary stage, while they were prominently low in the advanced stage.Exostotic bone formation markedly appeared in the periostal hyperplastic region of active muscular traction. The hyperplastic periosteum was divided into the outer fibrous and inner osteogenic layers, where the enzymatic activities were found different to each other. Autoradiographic labelling in the normal and in initial stages appeared mainly in preosteoblasts of the inner layer and elongated fibroblasts of the outer layer, while active labelling was confined to the preosteoblasts in the advanced stage.In tooth supporting structures, osteolathyritic changes were prominent in the periodontium, i.e., repeated development of palisade arranged connective tissue cells and eosinophilic amorphous substance. The periodontium, which revealed marked morphological changes, showed low or negative enzymatic ctivities. Mean percentage of 3H-thymidine labelled cells in the periodontium differed in the root apical, the alveolar crest and the intermediated regions. A progressive decreased percentage of labelled cells was observed in the root apical region in the advanced stage.