| Summary: | The cytotoxicity of dental composites has been attributed to the release of
residual monomers from polymerized adhesive systems due to degradation
processes or the incomplete polymerization of materials. 2-Hydroxyethyl
methacrylate (HEMA) is one of the major components released from dental
adhesives. Cytotoxic effects due to high concentrations of HEMA have already
been investigated, but the influence of minor toxic concentrations for long-term
exposition on specific proteins such as type I collagen and tenascin has not been
studied in depth. The objective of this project was to study the effect of minor
toxic concentrations of HEMA on human gingival fibroblasts (HGFs) and human
pulp fibroblasts (HPFs), investigating modification in cell morphology, cell
viability, and the influence on type I collagen and tenascin proteins.
Different concentrations of the resin monomer and different times of
exposition were tested on both cell lines. The cell vitality was determined by MTT
assay, and high-resolution scanning electron microscopy analysis was performed
to evaluate differences in cell morphology before and after treatment. To evaluate
the variability in the expression and synthesis of procollagen α1 type I and
tenascin proteins on HGFs and HPFs treated with HEMA at different
concentrations immunofluorescence, RT-PCR and western blot analysis, were
carried out.
The treatments on HGFs with 3mmol/L HEMA, showed a strong reduction
of procollagen α1 type I protein at 72h and 96h, demonstrating that HEMA
interferes both with the synthesis of the procollagen α1 type I protein and its
mRNA expression.
The results obtained on HPFs treated with different concentrations of
HEMA ranging from 0,5mmol/L to 3mmol/L and for different exposition times
showed a strong reduction in cell viability in specimens treated for 96h and 168h,
while immunofluorescence and western blotting analysis demonstrated a
reduction of procollagen α1 type I and an overexpression of tenascin protein.
In conclusion, our results showed that the concentrations of HEMA we tested,
effect the normal cell production and activity, such as the synthesis of some
dental extracellular matrix proteins.
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