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Protective effect of chitosan oligosaccharide lactate against DNA double-strand breaks induced by a model methacrylate dental adhesive.

Szczepanska J, Pawlowska E, Synowiec E, Czarny P, Rekas M, Blasiak J, Szaflik JP - Med. Sci. Monit. (2011)

Bottom Line: Monomers of methacrylates used in restorative dentistry have been recently reported to induce DNA double-strand breaks (DSBs) in human gingival fibroblasts (HGFs) in vitro.Because such monomers may penetrate the pulp and oral cavity due to the incompleteness of polymerization and polymer degradation, they may induce a similar effect in vivo.Therefore, the protection against DSBs induced by methacrylate monomers released from dental restorations is imperative.

View Article: PubMed Central - PubMed

Affiliation: Department of Developmental Dentistry, Medical University of Lodz, Lodz, Poland.

ABSTRACT

Background: Monomers of methacrylates used in restorative dentistry have been recently reported to induce DNA double-strand breaks (DSBs) in human gingival fibroblasts (HGFs) in vitro. Because such monomers may penetrate the pulp and oral cavity due to the incompleteness of polymerization and polymer degradation, they may induce a similar effect in vivo. DSBs are the most serious type of DNA damage and if misrepaired or not repaired may lead to mutation, cancer transformation and cell death. Therefore, the protection against DSBs induced by methacrylate monomers released from dental restorations is imperative.

Material/methods: We examined the protective action of chitosan oligosaccharide lactate (ChOL) against cytotoxic and genotoxic effects induced by monomers of the model adhesive consisting of 55% bisphenol A-diglycidyl dimethacrylate (Bis-GMA) and 45% 2-hydroxyethyl methacrylate (HEMA). We evaluated the extent of DSBs by the neutral comet assay and the phosphorylation of the H2AX histone test.

Results: ChOL increased the viability of HGFs exposed to Bis-GMA/HEMA as assessed by flow cytometry. ChOL decreased the extent of DSBs induced by Bis-GMA/HEMA as evaluated by neutral comet assay and phosphorylation of the H2AX histone. ChOL did not change mechanical properties of the model adhesive, as checked by the shear bond test. Scanning electron microscopy revealed a better sealing of the dentinal microtubules in the presence of ChOL, which may protect pulp cells against the harmful action of the monomers.

Conclusions: ChOL can be considered as an additive to methacrylate-based dental materials to prevent DSBs induction, but further studies are needed on its formulation with the methacrylates.

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Related in: MedlinePlus

Viability of human gingival fibroblasts exposed for 6 h at 37°C to the mixture of methacrylate monomers containing 55% bisphenol A-diglycidyl dimethacrylate and 45% 2-hydroxyethyl methacrylate (w/w) (Bis-GMA/HEMA) at 0.1 mM Bis-GMA with or without a 1 h preincubation with chitosan oligosaccharide lactate (ChOL) at indicated concentrations. The viability was measured by flow cytometry with thiazole orange and propidium iodide. Displayed is the mean of three experiments of 5×104 measurements each, error bars denote standard deviation. The inset presents the viability of the cells exposed to ChOL singly. ** p<0.01, * p<0.05 as compared with control without preincubation with ChOL.
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f3-medscimonit-17-8-br201: Viability of human gingival fibroblasts exposed for 6 h at 37°C to the mixture of methacrylate monomers containing 55% bisphenol A-diglycidyl dimethacrylate and 45% 2-hydroxyethyl methacrylate (w/w) (Bis-GMA/HEMA) at 0.1 mM Bis-GMA with or without a 1 h preincubation with chitosan oligosaccharide lactate (ChOL) at indicated concentrations. The viability was measured by flow cytometry with thiazole orange and propidium iodide. Displayed is the mean of three experiments of 5×104 measurements each, error bars denote standard deviation. The inset presents the viability of the cells exposed to ChOL singly. ** p<0.01, * p<0.05 as compared with control without preincubation with ChOL.

Mentions: Bis-GMA/HEMA evoked a concentration-dependent decrease in the viability of HGFs with less than 10% of living cells at 0.5 and 1 mM (Figure 2). The EC50 value for this mixture was estimated to be 0.13 mM. In the next experiment, a 6-hour incubation with Bis-GMA/HEMA at 0.1 mM Bis-GMA was preceded by a 1-hour preincubation with ChOL at various concentrations. The results indicate a protective effect of ChOL against cytotoxic action of Bis-GMA/HEMA monomers (Figure 3). On the other hand, ChOL alone did not influence the viability of HGFs (Figure 3, inset).


Protective effect of chitosan oligosaccharide lactate against DNA double-strand breaks induced by a model methacrylate dental adhesive.

Szczepanska J, Pawlowska E, Synowiec E, Czarny P, Rekas M, Blasiak J, Szaflik JP - Med. Sci. Monit. (2011)

Viability of human gingival fibroblasts exposed for 6 h at 37°C to the mixture of methacrylate monomers containing 55% bisphenol A-diglycidyl dimethacrylate and 45% 2-hydroxyethyl methacrylate (w/w) (Bis-GMA/HEMA) at 0.1 mM Bis-GMA with or without a 1 h preincubation with chitosan oligosaccharide lactate (ChOL) at indicated concentrations. The viability was measured by flow cytometry with thiazole orange and propidium iodide. Displayed is the mean of three experiments of 5×104 measurements each, error bars denote standard deviation. The inset presents the viability of the cells exposed to ChOL singly. ** p<0.01, * p<0.05 as compared with control without preincubation with ChOL.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3539618&req=5

f3-medscimonit-17-8-br201: Viability of human gingival fibroblasts exposed for 6 h at 37°C to the mixture of methacrylate monomers containing 55% bisphenol A-diglycidyl dimethacrylate and 45% 2-hydroxyethyl methacrylate (w/w) (Bis-GMA/HEMA) at 0.1 mM Bis-GMA with or without a 1 h preincubation with chitosan oligosaccharide lactate (ChOL) at indicated concentrations. The viability was measured by flow cytometry with thiazole orange and propidium iodide. Displayed is the mean of three experiments of 5×104 measurements each, error bars denote standard deviation. The inset presents the viability of the cells exposed to ChOL singly. ** p<0.01, * p<0.05 as compared with control without preincubation with ChOL.
Mentions: Bis-GMA/HEMA evoked a concentration-dependent decrease in the viability of HGFs with less than 10% of living cells at 0.5 and 1 mM (Figure 2). The EC50 value for this mixture was estimated to be 0.13 mM. In the next experiment, a 6-hour incubation with Bis-GMA/HEMA at 0.1 mM Bis-GMA was preceded by a 1-hour preincubation with ChOL at various concentrations. The results indicate a protective effect of ChOL against cytotoxic action of Bis-GMA/HEMA monomers (Figure 3). On the other hand, ChOL alone did not influence the viability of HGFs (Figure 3, inset).

Bottom Line: Monomers of methacrylates used in restorative dentistry have been recently reported to induce DNA double-strand breaks (DSBs) in human gingival fibroblasts (HGFs) in vitro.Because such monomers may penetrate the pulp and oral cavity due to the incompleteness of polymerization and polymer degradation, they may induce a similar effect in vivo.Therefore, the protection against DSBs induced by methacrylate monomers released from dental restorations is imperative.

View Article: PubMed Central - PubMed

Affiliation: Department of Developmental Dentistry, Medical University of Lodz, Lodz, Poland.

ABSTRACT

Background: Monomers of methacrylates used in restorative dentistry have been recently reported to induce DNA double-strand breaks (DSBs) in human gingival fibroblasts (HGFs) in vitro. Because such monomers may penetrate the pulp and oral cavity due to the incompleteness of polymerization and polymer degradation, they may induce a similar effect in vivo. DSBs are the most serious type of DNA damage and if misrepaired or not repaired may lead to mutation, cancer transformation and cell death. Therefore, the protection against DSBs induced by methacrylate monomers released from dental restorations is imperative.

Material/methods: We examined the protective action of chitosan oligosaccharide lactate (ChOL) against cytotoxic and genotoxic effects induced by monomers of the model adhesive consisting of 55% bisphenol A-diglycidyl dimethacrylate (Bis-GMA) and 45% 2-hydroxyethyl methacrylate (HEMA). We evaluated the extent of DSBs by the neutral comet assay and the phosphorylation of the H2AX histone test.

Results: ChOL increased the viability of HGFs exposed to Bis-GMA/HEMA as assessed by flow cytometry. ChOL decreased the extent of DSBs induced by Bis-GMA/HEMA as evaluated by neutral comet assay and phosphorylation of the H2AX histone. ChOL did not change mechanical properties of the model adhesive, as checked by the shear bond test. Scanning electron microscopy revealed a better sealing of the dentinal microtubules in the presence of ChOL, which may protect pulp cells against the harmful action of the monomers.

Conclusions: ChOL can be considered as an additive to methacrylate-based dental materials to prevent DSBs induction, but further studies are needed on its formulation with the methacrylates.

Show MeSH
Related in: MedlinePlus