HEMA but not TEGDMA induces autophagy in human gingival fibroblasts.
Polymerized resin-based materials are successfully used in restorative dentistry. Despite their growing popularity, one drawback is the release of monomers from the polymerized matrix due to an incomplete polymerization or degradation processes. Released monomers are responsible for several adverse effects in the surrounding biological tissues, inducing high levels of oxidative stress. Reactive oxygen species are important signaling molecules that regulate many signal-trasduction pathways and play critical roles in cell survival, death, and immune defenses. Reactive oxygen species were recently shown to activate autophagy as a mechanism of cell survival and cell death. Although the toxicity induced by dental resin monomers is widely studied, the cellular mechanisms underlying these phenomena are still unknown. The aim of the study was to investigate the behavior of human gingival cells exposed to 2-hydroxy-ethyl methacrylate (HEMA) and triethylene glycol dimethacrylate (TEGDMA) to better elucidate the mechanisms of cell survival and cell death induced by resin monomers. Primary culture of human gingival cells were exposed to 3 mmol/L of HEMA or 3 mmol/L of TEGDMA for 24, 48, and 72 h. Morphological investigations were performed by transmission electron microscopy to analyze the ultrastructure of cells exposed to the monomers. The expression of protein markers for apoptosis (caspase - 3 and PARP) and autophagy (beclin - 1 and LC3B I/II) were analyzed by western blot to investigate the influence of dental resin monomers on mechanisms underlying cell death. Results showed that HEMA treatment clearly induced autophagy followed by apoptosis while the lack of any sign of autophagy activation is observed in HGFs exposed to TEGDMA. These data indicate that cells respond to monomer-induced stress by the differential induction of adaptive mechanisms to maintain cellular homeostasis.
Department of Biomedical and Neuromotor Sciences, University of Bologna Italy.
Gabriella
G
Teti
Department of Clinical Sciences and Stomatology, Polytechnic University of Marche Ancona, Italy.
Giovanna
G
Orsini
Department of Biomedical and Neuromotor Sciences, University of Bologna Italy.
Viviana
V
Salvatore
Department of Biomedical and Neuromotor Sciences, University of Bologna Italy.
Stefano
S
Focaroli
Department of Medical and Surgical Sciences, University of Bologna Italy.
Maria C
MC
Mazzotti
Department of Biomedical and Neuromotor Sciences, University of Bologna Italy.
Alessandra
A
Ruggeri
Department of Clinical and Molecular Sciences, Polytechnic University of Marche Ancona, Italy.
Monica
M
Mattioli-Belmonte
Department of Biomedical and Neuromotor Sciences, University of Bologna Italy.
Mirella
M
Falconi
adaptive cell response; apoptosis; autophagy; dental resin monomers; human gingival fibroblasts