Human and rat mononuclear cell proliferation show different sensitivity, in vitro, to single constituents of dental composite resins

The aim of this study was to evaluate the effect of 11 constituents of dent al composite resins on ConA-induced proliferation of rat mononuclear cells. We also wanted to compare the sensitivity of rat and human mononuclear cel ls, to find out if results from a rat cell assay could be extrapolated to h uman conditions. The variable used for this purpose was the dose at 50% inh ibition of proliferation (IDS,). Mononuclear cells derived from rat spleens and human venous blood were used. The effects of the substances on rat and human cell proliferation were evaluated with and without stimulation by Co ncanavalin A. The LD,, rank order of the tested substance categories was si milar for both species, i.e., the monomers inhibited at the lowest concentr ation, the stabilizer at intermediate, and the initiators at the highest co ncentrations. In spite of a similar inhibition rank order, there were signi ficant differences in sensitivity to the substances between the species. In conclusion, the results from this study together with the fact that the su bstances are handled by and used in humans, would favor the use of human ce lls when studying the effect of constituents of dental composite resins in vitro. (C) 2000 John Wiley & Sons, Inc.