Endochondral ossification of the condyle in rats on a strontium or low-calcium diet

The mechanism of abnormal endochondral ossification induced by administration of strontium salts was studied in the mandibular condyles of rats by radiographic, histologic, and histochemical methods. It was shown by radiographic and histologic findings that ossification of the mandibular ramus was clearly inhibited in rats fed a low-calcium diet and rats fed a strontium diet. The change in appearance of the mandibular condyles of the rats fed strontium was more severe than that in those fed low amounts of calcium. From the histochemical findings, it was suggested that the metabolic dysfunction of chondroitin sulfate, periodic acid-Schiff positive materials, and collagen in the hypertrophic zone of the condylar cartilage (or in the part corresponding to trabecular bone of the mandibular ramus) was one factor inhibiting normal endochondral ossification.