Fig. 1

NAC protects DPSCs and SCAP cells from cell death induced by different concentrations of bleaching agents, and clinical grade hydrogen peroxide. Human SCAP cells were treated with ⁵¹Cr and incubated for 1 h, after which the cells were washed twice to remove excess ⁵¹Cr, followed by their treatment with different concentrations of H₂O₂ in triplicates in the presence and absence of NAC. After 4-h incubation the supernatants were harvested and counted for released radioactivity using standard 4-h ⁵¹Cr release assay as described in Materials and Methods (a). DPSCs obtained from human teeth were treated with ⁵¹Cr and incubated for 1 h, after which the cells were washed twice to remove the excess ⁵¹Cr, followed by their treatment with different concentrations of H₂O₂ in triplicates in the presence and absence of NAC. After 4-h of incubation the supernatants were harvested and counted for released radioactivity using standard 4-h ⁵¹Cr release assay as described in Materials and Methods (b). Human SCAP cells were cultured (0.2 million/ ml) overnight in 12 well plates before they were treated with bleaching agents containing hydrogen peroxide in the presence and absence of NAC (20 mM) in triplicates for 24 h. Afterwards SCAP cells were detached and their viability was determined using propidium iodide (PI) staining followed by flow cytometric analysis (c). DPSCs obtained from human teeth were cultured (0.2 million/ ml) overnight in 12 well plates, before they were treated with bleaching agents containing hydrogen peroxide in the presence and absence of NAC (20 mM) in triplicates for 24 h. Afterwards DPSCs were detached and their viability was determined using propidium iodide (PI) staining followed by flow cytometric analysis (d). DPSCs obtained from human teeth were cultured (0.2 million/ml) overnight in 12 well plates, before they were treated with clinical grade hydrogen peroxide (5 mM) in the presence and absence of NAC (20 mM) for 24 h. Afterwards DPSCs were detached and their viability was determined by flow cytometric analysis of forward and side scatter (left two panels), Annexin V staining alone (middle two panels), or PI and Annexin V staining (right two panels). One of 3 representative experiments is shown in this Fig. (e). Human SCAP cells were cultured (0.2 million/ ml) overnight in 12 well plates, before they were treated with clinical grade hydrogen peroxide (5 mM) in the presence and absence of NAC (20 mM) for 24 h. Afterwards SCAP cells were detached and their viability was determined by flow cytometric analysis of forward and side scatter (left two panels), Annexin V staining (middle two panels), or PI and Annexin V staining (right two panels). One of 3 representative experiments is shown in this Fig. (f). DPSCs obtained from human teeth were stained with TVA™ dye as described in Materials and Methods section before they were treated with clinical grade hydrogen peroxide at the concentrations indicated in the figure in the presence and absence of NAC (20 mM) for 4 h. Afterwards CTL S6 Ultimate Fluorescent Analyzer was used to analyze the surviving cells as described in Materials and Methods section. One of 3 representative experiments is shown in this Fig. (g). Human SCAP cells were stained with TVA™ dye as described in Materials and Methods section before they were treated with clinical grade hydrogen peroxide at the concentrations indicated in the figure in the presence and absence of NAC (20 mM) for 4 h. Afterwards CTL S6 Ultimate Fluorescent Analyzer was used to analyze the surviving cells as described in Materials and Methods section. One of 3 representative experiments is shown in this Fig. (h)