Fig. 2. MTT reduction was examined as a measure of viability of human fetal osteoblast (hFOB) cells after exposure to H₂O₂. (A) There were no significant differences in cell viability in the group that underwent remifentanil pretreatment, (B) Cell viability was maintained when the cells were pretreated with 3-MA prior to remifentanil administration, (C) The application of H₂O₂ alone to hFOB cells at various concentrations resulted in a decrease of cell viability above a concentration of 100 µM.