The objective of the current study was to explore possible cellular responses to the methacrylate monomer 2-hydroxy-propylmethacrylate (HPMA) in vitro. HPMA is one of several methacrylates that are commonly used in resin-based dental materials. However, the toxic response to this monomer is not yet investigated.
Different cell cultures were exposed to different concentrations of HPMA (0–8 mM) for 24 hours. Changes in density of viable cells after exposure were measured using the MTT assay. Cell cycle analyses were performed using flow-cytometry and multicycle analysis software (Phoenics Flow Systems, San Diego, CA, USA). Cell death pattern was analyzed by fluorescence microscopy of cells stained with propidium iodide (PI) and Hoechst 33342.
HPMA exposure resulted in reduced SDH activity (MTT assay), altered cell growth pattern and increased cell death in a dose dependent manner in all investigated cell lines. Comparing the results with previous studies of other methacrylate monomers indicate that the response is different from all monomers except the structurally similar 2-hydroxy-ethylmethacrylate (HEMA).
Our results showed a dose dependent cytotoxic response to HPMA. The results suggest an underlying mechanism similar to the mechanism of HEMA-induced toxicity.