A Dual Zinc plus Arginine formulation attenuates the pathogenic properties of Porphyromonas gingivalis and protects gingival keratinocyte barrier function in an in vitro model

Figures & data

Table 1. Effects of the Dual Zinc plus Arginine aqueous solution, the Dual Zinc plus Arginine dentifrice, and the regular fluoride dentifrice on the hemolytic activity of P. gingivalis. A value of 100% was assigned to the hemolysis induced by P. gingivalis in the absence of compounds. Results are expressed as the means ± SD of triplicate assays from two independent experiments. *, significant inhibition (p < 0.05) compared to control (no compounds).

Compounds	Dilution	Relative hemolysis
None		100%
Dual Zinc plus Arginine aqueous solution	1/500	52.5 ± 1.7%*
	1/1000	57.2 ± 0.6%*
	1/2000	54.3 ± 2.9%*
	1/4000	61.1 ± 0.5%*
	1/8000	87.5 ± 2.2%*
	1/16000	104.6 ± 0.9%
Dual Zinc plus Arginine dentifrice	1/500	62.4 ± 1.2%*
	1/1000	61.1 ± 0.5%*
	1/2000	69.2 ± 0.1%*
	1/4000	74.0 ± 1.2%*
	1/8000	85.6 ± 3.3%*
	1/16000	105.7 ± 1.2%
Control fluoride dentifrice	1/500	114.7 ± 2.3%
	1/1000	94.4 ± 1.9%
	1/2000	106.7 ± 4.3%
	1/4000	106.4 ± 0.8%
	1/8000	98.6 ± 4.9%
	1/16000	92.4 ± 1.6%

Figure 1. Effects of the Dual Zinc plus Arginine aqueous solution, the Dual Zinc plus Arginine dentifrice, and the regular fluoride dentifrice on collagen degradation by P. gingivalis. Results are expressed as the means ± SD of triplicate assays two independent experiments. *, significant decrease (p < 0.05) compared to untreated control cells.

Figure 2. Time- and dose-dependent effects of the Dual Zinc plus Arginine aqueous solution, the Dual Zinc plus Arginine dentifrice, and the regular fluoride dentifrice on gingival keratinocyte tight junction integrity, as determined by monitoring TER. A 100% value was assigned to the TER values at time 0. Results are expressed as the means ± SD of triplicate assays. *, significant increase (p < 0.05) compared to untreated control cells. φ, significant increase (p < 0.05) compared to the regular fluoride dentifrice.

Figure 3. Time- and dose-dependent effects of the Dual Zinc plus Arginine aqueous solution, the Dual Zinc plus Arginine dentifrice, and the regular fluoride dentifrice on the paracellular permeability of gingival keratinocytes to FITC-dextran 4 (FD-4). Results are expressed as the means ± SD of triplicate assays. *, significant decrease (p < 0.05) compared to untreated control cells.

Figure 4. Immunofluorescence staining of the tight junction proteins occludin and zonula occludens-1 of gingival keratinocytes treated for 48 h with the Dual Zinc plus Arginine aqueous solution, the Dual Zinc plus Arginine dentifrice, and the regular fluoride dentifrice. Arrows indicate discontinuities in protein labeling. This analysis was performed three times; a representative experiment and a representative field of this experiment is presented.

Figure 5. Time- and dose-dependent protective effects of the Dual Zinc plus Arginine aqueous solution, the Dual Zinc plus Arginine dentifrice, and the regular fluoride dentifrice against P. gingivalis-mediated damage of gingival keratinocyte tight junction integrity as determined by monitoring TER values. A 100% value was assigned to the TER values at time 0. Results are expressed as the means ± SD of triplicate assays. *, significant increase (p < 0.001) compared to P. gingivalis-infected cells not treated with compounds. Φ, significant decrease (p < 0.05) compared to non-stimulated control cells. φ, significant increase (p < 0.05) compared to the regular fluoride dentifrice.

Figure 6. Protective effects of the Dual Zinc plus Arginine aqueous solution, the Dual Zinc plus Arginine dentifrice, and the regular fluoride dentifrice on the paracellular permeability of gingival keratinocytes to FITC-dextran 4 (FD-4) compromised by P. gingivalis. Results are expressed as the means ± SD of triplicate assays. *, significant decrease (p < 0.05) compared to P. gingivalis-stimulated cells.

Figure 7. Immunofluorescence staining of the tight junction proteins occludin and zonula occludens-1 in gingival keratinocytes following a 48-h treatment with P. gingivalis (MOI = 10⁴) in the absence and presence of the Dual Zinc plus Arginine aqueous solution, the Dual Zinc plus Arginine dentifrice, or the regular fluoride dentifrice. Arrows indicate discontinuities in protein labeling. This analysis was performed three times; a representative experiment and a representative field of this experiment is presented.

Figure 8. Effects of the Dual Zinc plus Arginine aqueous solution, the Dual Zinc plus Arginine dentifrice, and the regular fluoride dentifrice on the invasion of a gingival keratinocyte barrier by P. gingivalis. Results are expressed as the means ± SD of triplicate assays. *, significant decrease (p < 0.001) compared to P. gingivalis-infected cells not treated with the compounds.