Diacerein Downregulates Nfkb, Induces ALP Activity and Inhibits Osteoblast Apoptosis in Alveolar Bone of Rats with Periodontitis

<b>Objectives</b>: We evaluated the effect of diacerein, an anti-inflammatory drug, on the activity and survival of alveolar bone osteoblasts in rats with periodontitis. <b>Methods</b>: The rats with periodontitis received diacerein (PDG) or saline solution (PSG) for 7, 15 and 30 days. In gingiva samples, <i>Nfkb1</i> and <i>Bmp2</i> gene expressions were evaluated, and maxillae were processed for light and transmission electron microscopy. <b>Results</b>: In PDG, the tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) immunoexpression decreased in parallel with the increase in alkaline phosphatase (ALP) and bone area over time. At 15 and 30 days, <i>Nfkb1</i> expression decreased in PDG compared to PSG, whereas at 30 days, the <i>Bmp2</i> expression was greater in PDG than in PSG. Immunofluorescence for IL-10, an anti-inflammatory cytokine, was greater in PDG than in PSG at 15 and 30 days. In PSG, the significant increase in the number of TUNEL-positive osteoblasts was accompanied by the presence of osteoblasts with condensed chromatin nuclei or caspase-3-immunolabelled osteoblasts. In contrast, the number of TUNEL-positive osteoblasts was significantly lower in PDG than in PSG specimens at all time points. <b>Conclusions</b>: Therefore, the diacerein-induced TNF-α and IL-1β inhibitory effect caused <i>Nfkb1</i> downregulation and, hence, prevented apoptosis in osteoblasts. The increased ALP activity and IL-10 in PDG indicate that diacerein mitigates periodontitis impact on alveolar bone in rat molars.