An Ultrastructural Study of the Periodontal Ligament Fibroblasts and Osteoblasts in Insulin-deficient Diabetes

Abstract

To investigate metabolic changes of periodontal ligament (PDL) fibroblasts and osteoblasts in insulin-deficient diabetes, adult Sprague-Dawley rats were administered a streptozotocin (STZ) and, at 1-16 weeks after STZ administration, their lower mandibles were examined ultrastructurally. By inducing diabetes, PDL fibroblasts became flattened in cell profile and contained many autophagosomes including various cytoplasmic inclusions. In addition, multinucleated fibroblasts appeared in PDL exhibited various atrophic cellular structure. In electron microscopic autoradiography of ³H-proline utilization by PDL osteobalsts, STZ-induced diabetes resulted in marked reduction of ³H-proline incorporation and its secretion towards newly-formed osteoid by atrophic fllattened osteoblasts. These results suggest that diabetes-induced structural abnormalities and suppression of procollagen synthesis by PDL fibroblasts and osteoblasts are important risk factors in local periodontal diseases.