Effect of type 2 diabetes on the ability of B and T lymphocytes to stimulate osteoclastogenesis/osteoclastic activity in vitro

Abstract

BACKGROUND: Alveolar bone resorption is more severe in type 2 diabetes-potentiated periodontitis. The key cells responsible for bone resorption are the osteoclast and their quantity and activity are regulated by the RANK/RANKL/OPG system. One of the major RANKL-expressing sources in diseased periodontal tissue are activated B and T lymphocytes, therefore it was hypothesized that type 2 diabetes up-regulates B cell RANKL function. OBJECTIVE: The aim of this study was to compare the effect of diabetes on the ability of B and T lymphocytes to stimulate osteoclast activity. MATERIALS AND METHODS: Metabolic status (diabetic vs normal) of mice were established using either a low-fat diet (LFD) or high-fat diet (HFD). Spleen lymphocytes were harvested and purified, then cultured in different combinations with adherent mouse leukemic monocyte/macrophage cell line cells over dentin-coated wells and observed for osteoclastic activity that breaks down the dentin-coating. The area of clearance was used to represent the level of activity. RESULTS: No difference in osteoclastic activity were noted between the two metabolic statuses, between B or T cells, between lymphocyte stimulated or not. CONCLUSION: The findings counters our hypothesis, and are inconsistent with the currently available evidence. Repeat of the experiment is warranted before valid conclusion can be drawn from the data.