Objective: To study the effect of silicon dioxide (SiO(2)) on the activation of nuclear factor-kappaB (NF-kappaB) in THP-1 cell line.
Methods: THP-1 cells were incubated with a series of doses of SiO(2) (0, 100, 200 micro g/ml). The location of NF-kappaB p65 subunit (NF-kappaB/p65) in THP-1 cells was detected by immunofluorescence and laser scanning confocal microscope (LSCM). The expression of NF-kappaB/p65 in nuclei was measured by Western blot analysis.
Results: The majority of fluorescein isothiocyanate (FITC)-labelled NF-kappaB/p65 located in the nuclei 30 min after stimulation by 100 micro g/ml SiO(2), whereas the FITC-labelled NF-kappaB/p65 were mainly seen in the plasma of normal control cells. The expression of NF-kappaB/p65 in THP-1 nuclear protein was low in control group (0 micro g/ml SiO(2)) while it increased after stimulation by 100 micro g/ml SiO(2) and 200 micro g/ml SiO(2) for 15 min and 30 min. The level of NF-kappaB/p65 was comparatively increased with the increasing of doses and time. Lipopolysaccharides (LPS), an activator of NF-kappaB, had similar effect as SiO(2) on the activation of NF-kappaB/p65 in THP-1 cells.
Conclusion: SiO(2) could activate and internalize NF-kappaB in the THP-1 cell line.