Periodontitis is a bacteria-induced inflammatory disease associated with alveolar bone loss. Osteoclast is a
macrophage-lineage cell that exhibits phagocytic activity; however, osteoclast phagocytic activity has not been
demonstrated under pathologica...
Periodontitis is a bacteria-induced inflammatory disease associated with alveolar bone loss. Osteoclast is a
macrophage-lineage cell that exhibits phagocytic activity; however, osteoclast phagocytic activity has not been
demonstrated under pathological conditions. Diabetes is a pathological condition that exacerbates alveolar bone loss
via periodontitis; therefore, we examined phagocytic osteoclasts in diabetic rats that had periodontitis. The rats were
divided into the control (C), periodontitis (P), and diabetes with periodontitis (DP) groups. Diabetes and periodontitis
were induced by streptozotocin injection and ligature of the mandibular first molars, respectively. On days 3 and 20
after the ligature, the rats were sacrificed, and osteoclasts containing inclusions were quantified by tartrate-resistant
acid phosphatase staining. On day 3, there were more osteoclasts containing inclusions in the DP group than in the C
group. Among inclusions, osteocyte-like cells and dense bodies were more frequently observed in the DP group than
in the C group. Cytoplasm-like structures were elevated more in the DP group than in the C and P groups. However,
no differences were observed on day 20. Interestingly, some osteoclasts were in contact with the osteocytes within
the exposed lacunae and contained several inclusions within a large vacuole. Thus, the elevation of phagocytic
osteoclasts in rats with diabetes and periodontitis provides insight into the role of osteoclast phagocytic activity under
pathological conditions.