Nassar M, Dargham A, Jamleh A, Tamura Y, Hiraishi N, Tagami J. The Hormetic Effect of Arsenic Trioxide on Rat Pulpal Cells: An In Vitro Preliminary Study.
Eur J Dent 2020;
15:222-227. [PMID:
33126286 PMCID:
PMC8184270 DOI:
10.1055/s-0040-1718637]
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Abstract
Objectives
Despite the agreement that there is no longer any indication for arsenic use in modern endodontics, some concerns are surfacing about the minute amount of arsenic trioxide (As
2
O
3
) released from Portland cement-based materials. The present study investigated the effect of different concentrations of As
2
O
3
on rat pulpal cells and the efficacy of
N
-acetylcysteine (NAC) in preventing As
2
O
3
-mediated toxicity.
Materials and Methods
Cytotoxicities of 50, 10, or 5 µm As
2
O
3
and the effect of cells co-treatment with 50 µm As
2
O
3
and 5,000 µm NAC or 500 µm NAC were tested at 24 hours or 3 days. Cell viability was assessed by means of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and cellular morphological changes were observed under phase contrast microscope.
Statistical Analysis
Two-way analysis of variance with Tukey’s post-hoc test was used to evaluate differences between the groups (α = 0.05).
Results
At both exposure times, 50 µm As
2
O
3
resulted in lower optical density (OD) values when compared with 10 or 5 µm As
2
O
3
. At 24 hours, 10 µm As
2
O
3
resulted in a higher OD value compared with the control; however, at 3 days the difference was statistically insignificant. At each exposure time, the OD value of 5 µm As
2
O
3
group was comparable to the control and 10 µm As
2
O
3
group. There were no significant differences between 50 µm As
2
O
3
group and 500 μm NAC+50 μm As
2
O
3
group; however, these two groups had lower OD values when compared with 5,000 μm NAC+50 μm As
2
O
3
group at 24 hours and 3 days. The latter group showed significantly lower OD value in comparison with the control at 24 hours and 3 days. Control cells were polygonal-shaped while 50 µm As
2
O
3
-treated cells exhibited contracted and spherical morphology with increased intercellular spaces. At 24 hours, 10 μm and 5 µm As
2
O
3
-treated cells were slightly hypertrophic. Cells co-treated with NAC and As
2
O
3
showed increased intercellular spaces and lower cellular density compared with the control.
Conclusions
As
2
O
3
displayed a hormetic effect on pulpal cells; however, the proliferative effect induced by low As
2
O
3
concentrations should be interpreted with caution. NAC did not prevent As
2
O
3
-mediated toxicity; however, it demonstrated potential for ameliorating this toxicity.
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