Influence of Baicalin on the Expression of Receptor Activator of Nuclear Factor-κB Ligand in Cultured Human Periodontal Ligament Cells

Abstract

Background: Baicalin is a flavonoid purified from the medicinal plant Scutellaria baicalensis Georgi. It has been reported that baicalin exhibits antibacterial, anti-inflammatory and analgesic effects and can inhibit nuclear factor-ĸB activation. Periodontal disease is a chronic infective disease of the periodontium caused by bacteria present in dental plaque inducing alveolar bone resorption until teeth are lost. Human periodontal ligament (HPDL) is the connective tissue between alveolar bone and tooth. Receptor activator of nuclear factor-ĸB ligand (RANKL), a member of the tumor necrosis factor (TNF) ligand family, plays an important role in osteoclastogenesis from osteoclast precursors to mature osteoclasts. In this study we investigate the effects of baicalin on RANKL protein production and messenger RNA (mRNA) expression induced by IL-1β in cultured HPDL cells. Methods: To induce RANKL expression, IL-1β was added to serum-free medium HPDL cells and incubated. Various concentrations of baicalin (0, 0.001, 0.01 and 0.1 µg/ml) were added to the medium and the cells were treated for 0, 12, 24, 48 and 72 h, respectively. RANKL in the cells was detected using immunocytochemistry. The mRNA of RANKL, osteoprotegerin (OPG) and cyclooxygenase-2 (COX-2) were measured by semiquantitative reverse transcription-polymerase chain reaction. Results: The expression of RANKL at mRNA and protein levels in HPDL cells was stimulated by IL-1β. Baicalin suppressed IL-1β-induced RANKL and COX-2 production at a concentration of 0.01 µg/ml. The most prominent effect was observed with 48 h of baicalin treatment. The inhibition of baicalin on the rhIL-1β-stimulated OPG expression was first apparent at 24 h after the start of treatment, however it did not reach significant differences. Conclusions: The data suggest that baicalin may inhibit RANKL mRNA expression via the suppression of COX-2 expression induced by IL-1β. In addition to its antibacterial and anti-inflammatory properties, baicalin was shown to be effective in periodontitis and alveolar bone resorption.

Response of Human Periodontal Ligament Cells to Baicalin

“…It is important to note that PDL fibroblasts influence osteoclastogenesis. Wang et al 31 found that baicalin could inhibit the RANKL mRNA expression induced by interleukin‐1β in cultured HPLCs. The present results are consistent with that notion.…”

Baicalin inhibits toll-like receptor 2/4 expression and downstream signaling in rat experimental periodontitis

“…Furthermore, baicalin inhibited the pro-inflammatory gene expression via down-regulating the TLRs/NF-κB signaling, such as COX-2, iNOS, TNF-α , IL-6, IL-13 and HMBG-1 in cervical tissue and colon tissue [11,30,32]. In addition, baicalin inhibited the production of IL-1β, IL-8, PGE2, leukotriene B4 (LTB4), COX-2, RANKL/OPG ratio, and inhibited the NF-κB, p38 MAPK in many types of cells involved in the process of periodontitis, such as human gingival fibroblasts, periodontal ligament cells, oral keratinocytes and cultured osteoblasts [19,20,[34][35][36]. In our study, baicalin down-regulated of HMGB1, TNF-α, IL-1β, and MPO in gingival tissues by down-regulating the TLR2 and TLR4/MyD88/ NF-κB signaling, and reduced inflammatory infiltrates and MPO production possibly by affecting these types of inflammatory cells during the process of periodontitis.…”

The effect of the coumarin-like derivative osthole on the osteogenic properties of human periodontal ligament and jaw bone marrow mesenchymal stem cell sheets

“…Functional ingredients derived from TCM have been shown to be powerful tools for the activation of adult stem cells for tissue regeneration, leading to the use of some of these molecules as useful adjuvants in cell processing technology and periodontal tissue engineering applications, sometimes as a substitute for recombinant human growth factors [39,40]. Particularly, osthole is a fundamental ingredient of coumarin compounds that are the main pharmaco-components of Fructus cnidii [41].…”