Preventive and Therapeutic Effects of Lactiplantibacillus plantarum HD02 and MD159 through Mast Cell Degranulation Inhibition in Mouse Models of Atopic Dermatitis

Abstract

As the relationship between the gut microbiome and allergies becomes better understood, targeted strategies to prevent and treat allergies through gut microbiome modulation are being increasingly developed. In the study presented herein, we screened various probiotics for their ability to inhibit mast cell degranulation and identified Lactiplatibacillus plantarum HD02 and MD159 as effective candidates. The two strains significantly attenuated vascular permeability induced by mast cell degranulation in a passive cutaneous anaphylaxis (PCA) model and, in the MC903-induced murine atopic dermatitis (AD) model, demonstrated comparable preventive effects against allergies, reducing blood levels of MCPT-1 (mast cell protease-1) and total IgE. In the house dust mite (HDM)-induced murine AD model, both L. plantarum HD02 and MD159 showed therapeutic effects, with L. plantarum HD02 demonstrating superior efficacy. Nevertheless, L. plantarum MD159 better suppressed transepidermal water loss (TEWL). Furthermore, L. plantarum HD02 and MD159 significantly increased the number of splenic Foxp3⁺ regulatory T cells, with L. plantarum MD159 having a more pronounced effect. However, only L. plantarum HD02 achieved a reduction in immune cells in the draining lymph nodes. Our findings highlight L. plantarum HD02 and MD159 as promising candidates for the prevention and treatment of allergies, demonstrating significant efficacy in suppressing mast cell degranulation, reducing the number of allergy biomarkers, and modulating immune responses in experimental models of AD. Their distinct mechanisms of action suggest potential complementary roles in addressing allergic diseases, underscoring their therapeutic promise in clinical applications.

Keywords: L. plantarum; allergy; atopic dermatitis; mast cell degranulation; probiotics.

Figure 1

Screening of probiotic strains for the inhibition of mast cell degranulation via the β-hexosaminidase assay. Various probiotic strains were tested to identify those capable of inhibiting IgE-induced mast cell degranulation using a mast cell line RBL-2H3 and β-hexosaminidase assay. Each probiotic strain was assessed for inhibitory effects in the form of (A) the bacteria and (B) their culture supernatants. Statistical analysis was performed only on probiotic strains that inhibited mast cell degranulation by 40% or less in (A). Data are represented as the mean ± SD. **, p < 0.01 and ***, p < 0.001 versus the MRS group.

Figure 2

Inhibition of IgE-induced mast cell degranulation by L. plantarum HD02 and MD159 in a PCA mouse model. To investigate the ability of probiotic strains to inhibit mast cell degranulation in vivo, a murine model of PCA was created according to the experimental scheme displayed in (A). Degranulation of mast cells was measured by the extent to which Evans blue, administered through the tail vein along with the antigen DNP-HSA, leaked into the ear skin. Representative photographs are shown in (B), and the amount of Evans blue extracted from both ears is presented in dot plots in (C). i.d., intradermal; i.v., intravenous; p.o., oral; Ag, antigen; QD, once a day; *** p < 0.001.

Figure 3

Prevention of allergic response by L. plantarum HD02 and MD159 in an MC-903-induced AD mouse model. To assess the preventive effects of L. plantarum HD02 and MD159, the mice were induced with AD based on the experimental scheme presented in (A). Representative images of the ear skin are shown in (B), and changes in ear thickness are shown graphically in (C). Blood levels of total IgE (D) and MCPT-1 (E) are also shown. Data are presented as the mean ± SEM. QD, once a day; p.o., oral; *** p < 0.001.

Figure 4

Therapeutic effects of L. plantarum HD02 and MD159 in an HDM-induced AD mouse model. The mice were induced with AD using HDM and treated with HD02 or MD159 according to the experimental scheme shown in (A). Representative images of dorsal skin are shown in (B), and changes in dermatitis scores are presented graphically in (C). The number of scratches (D), total IgE levels in the blood (E), and TEWL on the dorsal skin (F) were measured. Data are presented as the mean ± SEM. BIW, twice weekly; QW, once weekly; QD, once a day; p.o., oral; * p < 0.05; ** p < 0.01; *** p < 0.001.

Figure 5

Inhibition of epidermal layer thickness and mast cell infiltration by L. plantarum HD02 and MD159 in an HDM-induce AD mouse model. In a mouse model of HDM-induced AD, skin legions were analyzed. Paraffin sections were stained with H&E to measure the thickness of the epidermal layer (A,B) and toluidine blue to observe mast cell infiltration (C,D). The graphs display the thickness of the epidermal layer (B) and the number of infiltrated mast cells (D). Data are presented as the mean ± SEM *** p < 0.001.

Figure 6

Regulation of immune responses by L. plantarum HD02 and MD159 in an HDM-induced AD mouse model. The involvement of L. plantarum HD02 and MD159 in regulating immune responses was investigated in a mouse model of HDM-induced AD by analyzing the draining lymph node, ALN, and spleen. The expressions of il-4 and ifng in the ALN were examined using qRT-PCR (A) The numbers of total cells, T cells, and B cells in the ALN were counted (B). In the spleen, the ratio of Foxp3+ Treg cells among total T cells was measured via flow cytometric analysis (C). Data are presented as mean ± SEM. Dexa, dexamethasone; * p < 0.05; ** p < 0.01; *** p < 0.001.