ABSTRACT
OBJECTIVE: To evaluate whether the reduction/prevention of triethylene glycol dimethacrylate (TEGDMA)-induced decrease of intracellular glutathione (GSH) protects human periodontal ligament fibroblasts (HPLF) against cell death. METHODS: HPLF were preincubated for 30 min with exogenous GSH and then treated with TEGDMA (2.5 mM) with/without GSH (0.5-2.5-5 mM) for the following incubation exposure types: 6h (GI); 6h followed by 18 h recovery time in presence (GII) or absence (GIII) of exogenous GSH; 24 h without recovery time (GIV). TEGDMA-cytotoxicity and intracellular glutathione were assessed by Hoechst 33342 and monobromobimane (MBBr) assays. Data were statistically analyzed with Bonferroni ANOVA (p<0.05). RESULTS: Preincubation with exogenous GSH increased the intracellular GSH-concentration. TEGDMA was cytotoxic at all treatment times except at 6h (GI) (94±7% of control). In GII the treatment with TEGDMA alone (59±7%) showed no different results to cultures exposed to TEGDMA and GSH. Exogenous GSH had no effect on the TEGDMA-induced cytotoxicity also in the GIII and GIV. Thus, a combined incubation with GSH did not prevent the cytotoxicity of TEGDMA, despite of a significant increase of intracellular GSH-concentration in the presence of exogenously supplied GSH. SIGNIFICANCE: The glutathione-decreasing effect of TEGDMA is not the major cause of TEGDMA-induced cytotoxicity, indicating more complex mechanisms, which are causative for TEGDMA-cytotoxicity in HPLF.
Subject(s)
Composite Resins/toxicity , Glutathione/metabolism , Periodontal Ligament/drug effects , Polyethylene Glycols/toxicity , Polymethacrylic Acids/toxicity , Analysis of Variance , Benzimidazoles/metabolism , Bridged Bicyclo Compounds/metabolism , Cell Death/drug effects , Cell Survival/drug effects , Cells, Cultured , Fibroblasts/drug effects , Fibroblasts/metabolism , Fluorescent Dyes/metabolism , Glutathione/administration & dosage , Glutathione/pharmacology , Humans , Periodontal Ligament/cytology , Periodontal Ligament/metabolism , Reactive Oxygen Species/metabolismABSTRACT
INTRODUCTION: This study proposed to investigate aspects of cell proliferation and death in the epithelium of radicular (RCs) and dentigerous (DCs) cysts. METHODS: Serial sections of 17 RCs and 9 DCs were prepared for immunohistochemical detection of caspase-3, Bcl-2, and Ki-67 antigens. RESULTS: Caspase-3 was detected mainly in the suprabasal and superficial epithelial cells of RCs and DCs, whereas Ki-67 was detected predominantly in the basal layer. Both markers had significant expression in hyperplastic epithelium related to an intense inflammation in the capsule. Immunoreactivity for Bcl-2 was restricted to the basal layer and was significantly higher in atrophic epithelium of DCs than that of RCs. CONCLUSIONS: These results suggest that epithelial proliferation is balanced by apoptosis and that the presence of inflammation inhibits the Bcl-2 expression. DCs and RCs have different formation mechanisms but have similar biological behavior in the presence of intense inflammatory infiltrate.
