Wenshen decoction suppresses inflammation in IL-33-induced asthma murine model via inhibiting ILC2 activation

Abstract

Background: Wenshen decoction, consisting of Epimedium brevicornu Maxim, Morinda officinalis How and Cnidium monnieri (L.) Cusson, has favorable efficacy in the treatment of asthma in China.

Methods: The present study investigated the potential immunomodulatory mechanism underlying the therapeutic effects of Wenshen decoction on mouse asthma.

Results: Oral Wenshen decoction could ameliorate the production of IL-4, IL-5, IL-13 in the bronchoalveolar lavage fluid (BALF), reduce serum IgE, and improve the airway hyperresponsiveness (AHR) and airway inflammation in the BALB/c mice after intranasal treatment with recombinant IL-33. Moreover, Wenshen decoction reduced ILC2 and RORα mRNA expression, decreased the mRNA expression of ICOS and ST2 in the lung, but significantly increased the production of IFN-γ.

Conclusions: Our study indicates that Wenshen decoction may inhibit the activation of ILC2 through the IL-33/ST2/ICOS pathway to further suppress airway inflammation and AHR in the asthmatic mice, and the increased IFN-γ might be related to the effects of Wenshen decoction on ILC2.

Keywords: Asthma; ILC2; Wenshen decoction; traditional Chinese medicine.

Figure 1

Experimental protocol for IL-33-induced asthmatic model and treatments.

Figure 2

Effect of Wenshen decoction on the airway resistance in mice under different concentrations of methacholine. Data are show as means ± SEM (n=6). **P<0.01, ****P<0.0001, control group vs. IL-33 group; ^#P<0.05, ^##P<0.01, ^###P<0.001, PRE, WSF, and CO groups vs. IL-33 group; ^&P<0.05, CO group vs. WSF group. Control, control group; IL-33, IL-33-treated group; PRE, prednisone acetate group; WSF, Wenshen decoction group; CO, prednisone and Wenshen decoction group.

Figure 3

Effect of Wenshen decoction on the BALF inflammatory cells. At 24 h after the last IL-33-challenge, the total cell counts and differential cell counts were determined. Data are show as means ± SEM (n=6). **P<0.01, control group vs. IL-33 group; ^#P<0.05, ^##P<0.01, PRE, WSF, and CO groups vs. IL-33 group; ^&P<0.05, PRE group vs. WSF group, PRE group vs. CO group. Control, control group; IL-33, IL-33-treated group; PRE, prednisone acetate group; WSF, Wenshen decoction group; CO, prednisone and Wenshen decoction group; Leu, white blood cells; Lym, lymphocytes; Neu, neutrophils; Bas, basophils; Mon, monocytes; Eos, eosinophils. BALF, bronchoalveolar lavage fluid.

Figure 4

Effect of Wenshen decoction on the histopathology of the lung. Inflammation was evaluated in the lung by analyzing inflammatory cell infiltration after H&E staining. Magnification: 200×. Control, control group; IL-33, IL-33-treated group; PRE, prednisone acetate group; WSF, Wenshen decoction group; CO, prednisone and Wenshen decoction group.

Figure 5

Effect of Wenshen decoction on the BALF IL-4 (B), IL-5 (C) and IL-13 (D) in BALF and serum IgE (A). At 24 h after the last IL-33 challenge, BALF and serum were collected for the measurement of these cytokines by ELISA. Data are show as means ± SEM (n=6). **P<0.01, ***P<0.001, control group vs. IL-33 group; ^##P<0.01, PRE, WSF, and CO groups vs. IL-33 group; ^&P<0.05, ^&&P<0.01, PRE group vs. WSF group, PRE group vs. CO group. Control, control group; IL-33, IL-33-treated group; PRE, prednisone acetate group; WSF, Wenshen decoction group; CO, prednisone and Wenshen decoction group. BALF, bronchoalveolar lavage fluid.

Figure 6

Effect of Wenshen decoction on ILC2 in the lung. Data are show as means ± SEM (n=6). ***P<0.001, control group vs. IL-33 group; ^#P<0.05, PRE, WSF, and CO groups vs. IL-33 group; ^&P<0.05, ^&&P<0.01, WSF group vs. CO group. Control, control group; IL-33, IL-33-treated group; PRE, prednisone acetate group; WSF, Wenshen decoction group; CO, prednisone and Wenshen decoction group.

Figure 7

Effect of Wenshen decoction on mRNA expression of RORα (A), ST2 (B), ICOS (C), GATA-3 (D) and T-bet (E). Data are show as means ± SEM (n=6). **P<0.01, control group vs. IL-33 group; ^#P<0.05, ^##P<0.01, PRE, WSF, and CO groups vs. IL-33 group. Control, control group; IL-33, IL-33-treated group; PRE, prednisone acetate group; WSF, Wenshen decoction group; CO, prednisone and Wenshen decoction group. RORα, receptor-related orphan receptor-α.

Figure 8

Effects of Wenshen decoction on IFN-γ expression in the spleen. Data are show as means ± SEM (n=6). ^#P<0.05, PRE, WSF, and CO groups vs. IL-33 group; ^&P<0.05, PRE group vs. WSF group, WSF group vs. CO group. Control, control group; IL-33, IL-33-treated group; PRE, prednisone acetate group; WSF, Wenshen decoction group; CO, prednisone and Wenshen decoction group.