Background: Various assays are used to evaluate the cytotoxic effect of chemicals on cultured cells. The sulforhodamine B (SRB) colorimetric assay is based on the ability of the SRB dye to bind basic amino acid residues on proteins. In contrast, the MTT (dimethylthiazol-diphenyltetrazolium bromide) colorimetric assay is based on mitochondrial uptake and succinate dehydrogenase reduction of soluble, yellow, MTT tetrazolium salt to an insoluble blue MTT formazan product. The aim of this study was to evaluate the cytotoxicity of a Thai herb by comparing MTT and SRB assay results. Methods: Mouse fibroblast (L929) cells were exposed to 0.01, 0.1, 0.25, and 0.5% (w/v) of a Thai herb in a 96-cluster well culture plate for 24 h. Cell viability after exposure to the Thai herb was determined by MTT and SRB assays in separate tissue culture plates. The two assays were compared using intra-class correlation coefficient (ICC) analysis. Results: There were no significant differences between the two cytotoxicity assays (p > 0.05). The ICC values showing the agreement of the two assays in the negative and positive control groups and Thai herb concentrations of 0.01, 0.1, 0.25, and 0.5% were 0.93 and 0.99 and 0.53, 0.51, 0.95, and 0.98, respectively. Conclusions: In general, the MTT and SRB assays performed similarly, exhibiting moderate to excellent correlation in the evaluation of the cytotoxicity of a Thai herb.

No abstract

No abstract

Objectives:This is an in vitro study to develop a formulation of a hypochlorite solution for root canal irrigation that lacks a chlorinated odor. The antibacterial effect, tissue dissolution efficacy, and the cytotoxicity of the solution were assessed in cell culture and were compared with those of commercial sodium hypochlorite (NaOCl) solutions.Materials and Methods:Trichloroisocyanuric acid (TCA) was used as the source of hypochlorite ions in solution. All required properties of the NaOCl irrigant were evaluated and compared with those of original 2.5% NaOCl solutions currently in use.Results:Our results revealed that a TCA 3.5% + 1/6 Buffer-1 solution passed the short-term stability test. Moreover, no odor of chlorine gas was detected by three independent observers. The hypochlorite ion content and pH were stable over an incubation period of 4 weeks. The new solution did not differ from commercial products in terms of the dissolution property on bovine pulpal tissue (P > 0.05). Moreover, the antibacterial effect of this solution on Enterococcus faecalis did not differ from that of the commercial products (P > 0.05). In addition, our biocompatibility analysis demonstrated no difference among the tested solutions (P > 0.05).Conclusions:According to the results of all properties tested, TCA 3.5% + 1/6 Buffer-1 could be considered an option for NaOCl irrigation with the benefit of no detectable chlorine odor.

Objective:To evaluate the cytotoxic and the proliferative effect of cuttlefish bone on MC3T3-E1 osteoblast cell line.Materials and Methods:MC3T3-E1 cells were treated with 0.5, 1, 5, 25, 50, 100, or 200 μg/ml cuttlefish bone powder (CBP). Cytotoxicity was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. This assay was also used to determine cell proliferation over 16 days of treatment with 0.5, 25, or 100 μg/ml CBP.Results:CBP was not cytotoxic to MC3T3-E1 cells at any concentration. The percentage of cell viability in the 0.5–200 μg/ml CBP groups dose dependently decreased from 107.52 ± 11.03 to 92.48 ± 5.60%; however, the differences between the groups or the negative control group were not significant. At 16 days, 0.5, 25, and 100 μg/ml CBP groups showed 123.19 ± 10.07%, 126.02 ± 15.69%, and 133.33 ± 11.74% proliferation, respectively, that were significantly higher than that of the control group.Conclusion:These results indicate that CBP promotes osteoblast proliferation and may be a potential material to increase the number of osteoblasts in a bone defect in the oral cavity.