Evaluation of the irritancy and hypersensitivity potential following topical application of didecyldimethylammonium chloride

Figures & data

Figure 1. Chemical structure of DDAC.

Table 1. Body/organ weight of female Balb/c mice dermally exposed to DDAC.

	DDAC (w/v)
Parameter	0%	0.25%	0.50%	1%
Body Weight (g)	19.73 ± 0.47	18.99 ± 0.57	17.46 ± 0.30*	16.90 ± 0.32**
Kidney Weight
mg	263 ± 3	219 ± 11	225 ± 5	221 ± 9
%bw^a	1.23 ± 0.03	1.20 ± 0.02	1.29 ± 0.05	1.30 ± 0.04
Spleen Weight
mg	94 ± 2	S3 ± 11	92 ± 13	97 ± 5
%bw	0.48 ± 0.01	0.43 ± 0.02	0.53 ± 0.04	0.57 ± 0.03
Thymus Weight
mg	53 ± 6	59 ± 2	44 ± 2	39 ± 4#
%bw	0.26 ± 0.02	0.31 ± 0.01	0.25 ± 0.01	0.23 ± 0.03
Liver Weight
mg	917 ± 36	910 ± 46	838 ± IS	S00 ± 22##
%bw	4.64 ± 0.08	4.79 ± 0.16	4.80 ± 0.10	4.73 ± 0.09

^a bw: body weight.

Values are expressed as means (± SE) for each group.

Significantly different from acetone controls at *p< 0.05 or **p < 0.01 Linear Trend (##p < 0.001, #p < 0.05)

Figure 2. Irritancy and allergic sensitization potential after dermal exposure to DDAC. (A) Irritancy and (B) allergic sensitization potential of DDAC using the LLNA. Irritancy was determined using measurements collected at 24 h following the final DDAC exposure (3 days). DPM represent [³H]-thymidine incorporation into DLN cells from the BALB/c mice following exposure to vehicle or concentration of DDAC (0.0625–1%). SI value is the stimulation index (fold-change over vehicle control). Bars represent mean (± SE) of five mice per group.

Figure 3. Local and systemic IgE levels following dermal DDAC exposure. Percentages of (A) B-cells and (B) IgE⁺ B-cells among total lymphocytes in the DLN and (C) total serum IgE (C) on Day 10 following 4 days of DDAC application. Bars represent mean (± SE) of five mice per group.

Figure 4. Increases in activated leukocytes following dermal exposure to DDAC. Percentages of (A) CD44^highCD4⁺ cells, (B) CD44^highCD8⁺ cells, (C) CD86⁺ dendritic cells and (D) CD86⁺ B-cells among total lymphocytes on Day 10 following 4 days of DDAC application. Bars represent mean (± SE) of five mice per group.

Table 2. Effects of dermal exposure to DDAC on DLN cell number and lymphocyte sub-population in female Balb/c mice.

	DDAC
Parameter	0%	0.25%	0.05%	1%
DLN number (×10^6)	3.65 ± 0.47	15.2 ± 0.83**	15.5 ± 1.08**	17.0 ± 1.42**
B-cell number
(×10^6)	0.51 ± 0.09	2.8 ± 0.13**	2.8 ± 0.21**	4.0 ± 0.32**
% of DLN					14.12 ± 1.5	18.52 ± 0.27*	18.02 ± 1.45	23.80 ± 0.46**
CD4 ^+ T-cell number
(×10^6)	2.2 ± 0.29	8.4 ± 0.47**	8.6 ± 0.68**	8.7 ± 0.76**
% of DLN					60.04 ± 0.96	55.28 ± 0.25**	54.98 ± 0.25**	51.02 ± 0.50**
CD8^+-cells
(x 10^6)	0.92 ± 0.11	3.7 ± 0.21**	3.5 ± 0.32**	3.9 ± 0.29**
% of DLX					25.26 ± 0.66	24.46 ± 0.22	2490 ± 0.46	22.98 ± 0.51*
Dendritic cells
(×10^5)	0.4 ± 0.06	1.5 ± 0.08**	2.0 ± 0.11**	1.9 ± 0.19**
% of DLN					1.18 ± 0.14	0.96 ± 0.05	1.33 ± 0.08	1.15 ± 0.09

Mice were dermally exposed to vechicle (acetone) or different concentrations of DDAC for 4 consecutive days. The mice were euthanized 6 days after the final exposure, DLN were removed, and total cells counted. Numbers and frequency of B- and T-cells, and subsets of T-cells (CD4⁺ and CD8⁺), and dendritic cells were enumerated. Values represent the means (± SE) for each group. Significantly different from acetone controls at *p < 0.05 and **p < 0.01