Abstract
Asthma is a T helper 2 (Th2) cell-associated chronic inflammatory diseases characterized with airway obstruction, increased mucus production, and eosinophil infiltration. Conventional medications for asthma treatment cannot fully control the symptoms, and potential side effects are also the concerns. Thus, complement or alternative medicine (CAM) became a new option for asthma management. Ding Chuan Tang (DCT) is a traditional Chinese herbal decoction applied mainly for patients with coughing, wheezing, chest tightness, and asthma. Previously, DCT has been proved to improve children airway hyperresponsiveness (AHR) in a randomized and double-blind clinical trial. However, the mechanisms of how DCT alleviates AHR remain unclear. Since asthmatic features such as eosinophil infiltration, IgE production, and mucus accumulation are relative with Th2 responses, we hypothesized that DCT may attenuate asthma symptoms through regulating Th2 cells. Ovalbumin (OVA) was used as a stimulant to sensitize BALB/c mice to establish an asthmatic model. AHR was detected one day before sacrifice. BALF and serum were collected for immune cell counting and antibody analysis. Splenocytes were cultured with OVA in order to determine Th2 cytokine production. Lung tissues were collected for histological and gene expression analyses. Our data reveal that DCT can attenuate AHR and eosinophil accumulation in the 30-day sensitization asthmatic model. Histological results demonstrated that DCT can reduce cell infiltration and mucus production in peribronchial and perivascular site. In OVA-stimulated splenocyte cultures, a significant reduction of IL-5 and IL-13 in DCT-treated mice suggests that DCT may alleviate Th2 responses. In conclusion, the current study demonstrates that DCT has the potential to suppress allergic responses through the reduction of mucus production, eosinophil infiltration, and Th2 activity in asthma.
Highlights
Asthma is a chronic inflammatory disease that has several typical symptoms, such as bronchial hyperreactivity, mucus overproduction, airflow obstruction, and immune cells infiltration into the peribronchial and perivascular, especially eosinophils or neutrophils [1]
We investigated whether Ding Chuan Tang (DCT) can attenuate asthma symptoms through mediating T helper 2 (Th2) activity, eosinophil infiltration, or mucus production in ovalbumin- (OVA-) sensitized mice model
The results demonstrated that mucus production was conspicuous in OVA-challenged mice, while DCT significantly attenuated the accumulation level of mucus in peribronchial areas (Figure 5)
Summary
Asthma is a chronic inflammatory disease that has several typical symptoms, such as bronchial hyperreactivity, mucus overproduction, airflow obstruction, and immune cells infiltration into the peribronchial and perivascular, especially eosinophils or neutrophils [1]. Asthma has been considered as a T helper 2 (Th2) cell-associated inflammatory diseases. Th2-related cytokines, such as interleukin- (IL-) 4, IL-5, and IL-13, are important for the development of asthma [2]. IL-5 is indispensable for eosinophil activation, maturation, and survival [6]. The mature eosinophils are navigated into the lung by chemokines, causing eosinophilia [7]. IL-13 is involved in many features of asthma.
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