Evidence that HSP70 gene expression may be useful for assessing the cytocompatibility of dental biomaterials

In the current studies, we examined the possibility of using HSP70 gene regulation as a cytocompatibility test for dental biomaterials. For this reason, we assessed the effects of three metal salts, HgCl2, CuSO4 and NiCl2 on HSP70 gene expression in HeLa S3 cells using real-time Taqman quantitative PCR. Incubation of the cells for 4 h in medium containing HgCl2 (20 or 40 microM), CuSO4 (157, 313, 625 or 1250 microM) or NiCl2 (5000 and 10000 microM) significantly induced HSP70 mRNA. The real-time Taqman quantitative PCR was able to detect HSP70 mRNA induction at 4-fold lower concentrations of HgCl2 and 8-fold lower concentrations of CuSO4 than the Neutral Red cell viability assay. These results indicate that real-time Taqman quantitative PCR, in combination with the monitoring of cell viability, may be a valuable tool for distinguishing between specific HSP70 mRNA induction and cytocompatibility of metals in dental biomaterials.