RBL-2H3

Effect of Isoscopoletin on the Viability of HaCaT and RBL-2H3 Cells

Atopic dermatitis (AD) represents a chronic skin condition that shows rising occurrence rates and features both skin inflammation and allergic responses. Isoscopoletin, a plant-derived compound, has shown potential in treating skin diseases but its effects on AD are unknown.

To evaluate the physiological activity of isoscopoletin, first, the range that does not affect cell viability was determined. MTT assay was used to examine the range's effects on HaCaT and RBL-2H3 cells. HaCaT cell viability decreased significantly compared to the control group when treated with 80 μM and 160 μM isoscopoletin which showed values of 96.49 ± 0.29% and 89.87 ± 0.01% respectively (Fig. 1A). The viability of RBL-2H3 cells decreased significantly to 91.82 ± 1.03% at 80 μM and 85.19 ± 0.44% at 160 μM when compared to the untreated control group according to Fig. 1B). Cell viability remained consistent between both cell lines at concentrations under 40 μM. Therefore, isoscopoletin was applied in the following experiments at a concentration of 5–40 μM.

Fig. 1. Viability of HaCaT and RBL-2H3 cells treated with isoscopoletin (Seo D-Y, Park J-W, et al., 2024).

Effect of Polymethoxyflavonoids and Milk Proteins on Degranulation of Rat Basophilic Leukemia Cells (RBL-2H3)

Allergies are rising in developed countries, with type-I allergies causing significant reductions in quality of life. Degranulation of mast cells and basophils, triggered by IgE antibodies, is a key process in type-I allergies.

Miyake et al. investigated the combined anti-allergic effects of nobiletin and lactoferrin on degranulation in RBL-2H3 cells. To evaluate IgE-mediated degranulation, they employed a β-hexosaminidase release assay. The release of β-hexosaminidase from RBL-2H3 cells decreased significantly with PMF treatment, starting at 5 µM NOB and 10 µM TNG, but not with SNT (Fig. 2a). For milk proteins, significant inhibition began at 2 µg/mL LF and 170 µg/mL β-LG (Fig. 2b). NOB had the strongest inhibitory effect among PMF, followed by TNG and SNT. LF was more effective than β-LG among milk proteins. Therefore, NOB and LF were chosen to study the combined inhibitory effects on degranulation. At 50 µM NOB and 15 µg/mL LF, the β-hexosaminidase release rate was inhibited by 27% and 41%, respectively. When combined, NOB and LF inhibited release by 82% (Fig. 3).

Fig. 2. Effect of polymethoxyflavonoids and milk proteins on degranulation of RBL-2H3 cells (Miyake K, Tanaka M, et al., 2024).

Fig. 3. Effect of nobiletin and lactoferrin on degranulation of RBL-2H3 cells (Miyake K, Tanaka M, et al., 2024).