Effects of arecoline on cell growth, migration, and differentiation in cementoblasts

Triethylene-glycol-dimethacrylate induces caspase-mediated apoptotic cell death in cementoblasts by the regulation of JNK and p38 pathways-an in vitro study

Background/Purpose

Triethylene-glycol-dimethacrylate (TEGDMA) is one of the monomers used in composite resin matrix. Residual TEGDMA can be eluted from bulk fill composite resins and the amounts also increased with time. Composite resin used as root-end filling materials may invoke the critical biologic reactions in surrounding tissues. However, little is known about the effects of TEGDMA on cementoblasts. The aim of this study was to investigate the possible detrimental effects of murine cementoblast (OCCM.30) by TEGDMA in vitro.

Materials and methods

OCCM.30 cells were exposed to TEGDMA (0, 1, 2, 4 mM) for 24 h. Cell viability was determined by microculture tetrazolium assay. Flow cytometry was conducted to evaluate the cell cycle distribution and the type of cell death. Caspase-mediated apoptotic cascade and mitogen-activated protein kinase (MAPK) pathways were analyzed by Western blot.

Results

The concentrations of TEGDMA≧1 mM were found to significantly inhibit OCCM.30 cell viability in a dose-dependent manner (P < 0.05). TEGDMA dose-dependently induced apoptosis by the increase of sub-G1 population, early apoptotic cells, and later apoptotic cells. TEDGMA-induced apoptotic mechanisms were found to activate caspase 8, 9, and 3 in OCCM.30 cells, respectively (P < 0.05). In addition, both c-Jun N-terminal kinase (JNK) inhibitor JNK-in-8 and p38 inhibitor SB203580 dramatically reduced TEGDMA-induced caspase 8, 9, and 3 activations in OCCM.30 cells, respectively (P < 0.05).

Conclusion

Taken together, our results demonstrated that TEDGMA decreased cell viability and induced the apoptotic cell death in cementoblast. In addition, caspase-mediated cell apoptosis was found to be associated with JNK and p38 signal transduction pathways.

Sodium butyrate activates the extrinsic and intrinsic apoptotic processes in murine cementoblasts

Background

/purpose: The metabolic by-product butyric acid of Gram-negative anaerobic bacteria can invoke pathological effects on periodontal cells resulting in inflammation and further destruction of periodontium. However, limited researches on the effects of butyric acid on cementoblasts were reported. Therefore, this study aimed to investigate the type of cell death in murine cementoblast (OCCM.30) caused by adding the different concentrations of sodium butyrate to the cell culture.

Materials and methods

OCCM.30 cells were exposed to sodium butyrate (0, 2, 4, 8, 16 mM) for 48 h. Cell viability was determined by microculture tetrazolium assay. Cell cycle distribution and cell death were analyzed by flow cytometry. Caspase-mediated apoptotic cascade was evaluated by Western blot.

Results

The concentrations of sodium butyrate≧4 mM were found to inhibit cell viability of OCCM.30 cells in a dose-dependent manner (P < 0.05). Sodium butyrate elevated sub-G1 cell population which exhibited cell apoptosis in OCCM.30 cells (P < 0.05). In addition, early and later apoptotic cells were found in sodium butyrate-induced cell death. Sodium butyrate significantly stimulated the degradation of procaspases-3, -8, and -9 levels, respectively (P < 0.05). Simultaneously, sodium butyrate corresponded to augment the levels of cleaved forms of caspases-3, -8, and -9, respectively (P < 0.05).

Conclusion

Taken together, sodium butyrate is a cytotoxic agent and can induce apoptosis on cementoblasts. The pathway involved in apoptosis is activated by caspase family signaling pathways. These evidences may provide a new mechanistic insight into the mechanism of damage of cementoblasts during the development and progression of periodontitis.

BactericidalActivity of Crevicular Polymorphonuclear Neutrophils in Chronic Periodontitis Patients and Healthy Subjects under the Influence of Areca Nut Extract: An In Vitro Study

Arecanutchewing is an established risk factor for oral submucous fibrosis (OSMF), but its role in periodontal disease has not yet been defined. Thisstudy aimed to assess the effect of areca nut extracts (ANE) on the bactericidal activity of crevicular polymorphonuclear neutrophils (cPMNs) in healthy subjects and chronic periodontitis (CP) patients. An in vitro study was designed with an equal number of (n = 30) gingival crevicular fluid (GCF) samples collected from CP patients and healthy subjects. Bactericidal activity and hydrogen peroxide (H2O2) assays were performed with the GCF samples pre-treated with extracts of two varieties of areca nut: ripe and tender. Simultaneously, controls were also carried out with Hank’s balanced salt solution (HBSS) and catechin. Independent t-test and one-way analysis of variance (ANOVA), along with post-hoc analysis, were employed for statistical analysis. In both study groups, a significant reduction (p < 0.01)in the bactericidal activity was noted when the samples treated with the ripe areca nut (rANE) were compared with the tender variant (tANE). Similarly, H2O2 levels were significantly reduced (p < 0.001) in the rANE in contrast to tANE for both study groups. The above results were significant within the group but were found to be non-significant between the study groups, except when it was treated with HBSS (p < 0.001). In the present study, it was found that there was a reduction in the bactericidal activity and H2O2 production of cPMNs in both healthy subjects and CP patients in the presence of areca nut extract. Moreover, the effect of rANE on cPMNs was more detrimental than tANE.

Metabolic changes during periodontitis therapy assessed by real-time ambient mass spectrometry

It has been shown that bacteria in periodontally diseased patients can be recognized by the detection of volatile metabolites in the headspace of saliva by real-time ambient mass spectrometry. The aim of this study was to use this detection method to analyze the oral metabolome in diseased periodontitis patients before and after therapy to monitor disease evolution and healing events. Twelve patients with advanced chronic periodontal disease and 12 periodontally healthy controls served as test and control groups, respectively. Clinical data, subgingival plaque samples and saliva samples were collected at baseline (BL) and 3 months after treatment. The test group received non-surgical scaling and root planing using systemic antibiotics and the control group received one session of supragingival cleaning. Saliva samples from all subjects were analyzed with ambient mass spectrometry. Significant metabolic alterations were found in the headspace of saliva of periodontitis patients 3 months after the non-surgical periodontal treatment. Furthermore, the diseased group showed metabolic features after the treatment that were similar to the healthy control group. In addition, 29 metabolic features correlated with A. actinomycetemcomitans, 17 features correlated with P. gingivalis and one feature correlated with T. denticola. It was shown that headspace secondary electrospray ionization - mass spectrometry allows the detection of different volatile metabolites in healthy and diseased patients. It can be concluded that this rapid and minimally invasive method could have the potential to routinely diagnose and monitor periodontal diseases in the headspace of saliva samples and, eventually, in exhaled breath.