1.Effect of Shegan Mahuangtang and Its Pungent and Bitter Chinese Herbs on Airway Inflammation and Expression of TRPV1/TAS2R14 in Lung Tissue of Rat Model of Cold Asthma
Yamei YUAN ; Weidong YE ; Yue CHENG ; Qiuhui LI ; Jiaxin LIU ; Jiale QIAO ; Kun WANG ; Xiangming FANG
Chinese Journal of Experimental Traditional Medical Formulae 2024;30(21):1-9
ObjectiveTo investigate the effects of Shegan Mahuangtang and its pungent and bitter Chinese herbs on the expression of transient receptor potential vanilloid-1 (TRPV1) and bitter taste receptor 14 (TAS2R14) in the lung tissue of the rat model of cold asthma. MethodSeventy SD rats were randomized into 7 groups: normal, model, Shegan Mahuangtang, pungent Chinese herbs, bitter Chinese herbs (6.43 g·kg-1), dexamethasone (0.5 g·kg-1), and Guilong Kechuanning (10 g·kg-1). The rat model of cold asthma was established by intraperitoneal injection and subcutaneous injection of 10% ovalbumin (OVA) and aluminium hydroxide in the limbs, combined with 2% OVA atomization and cold (2-4 ℃) stimulation. The rats were treated with corresponding drugs by gavage and atomization, and the normal and model groups were treated with the same amount of normal saline for 3 weeks. After the last excitation, airway inflammation and cell proliferation were observed by hematoxylin-eosin (HE), periodic acid-Schiff (PAS), and Masson staining of the lung tissue. The levels of interleukin-5 (IL-5), tumor necrosis factor-α (TNF-α), thymic stromal lymphopoietin (TSLP), and transforming growth factor-β1 (TGF-β1) in the serum were measured by enzyme-linked immunosorbent assay (ELISA). The expression of TRPV1 and TAS2R14 was detected by immunofluorescence. The expression of TRPV1, TAS2R14, phospholipase Cβ2 (PLCβ2), B-cell lymphoma-2 (Bcl-2), and α-smooth muscle actin (α-SMA) in the lung tissue was determined by Western blot. ResultCompared with the normal group, the model group showed decreased water intake, food intake, and body weight, increased airway inflammatory cell infiltration, goblet cell proliferation, tissue fibrosis and collagen deposition, elevated levels of IL-5, TNF-α, TSLP, and TGF-β1 in the serum (P<0.01), upregulated expression of TRPV1, PLCβ2, and α-SMA, and downregulated expression of TAS2R14 and Bcl-2 (P<0.05, P<0.01). Compared with model group, Shecgan Mahuangtang, pungent Chinese herbs, and bitter Chinese herbs increased the water intake, food intake, and body weight, reduced the inflammatory cell infiltration and goblet cell proliferation, alleviated tissue fibrosis and collagen deposition, lowered the levels of IL-5, TNF-α, TSLP, and TGF-β1 in the serum (P<0.01), downregulated the expression of TRPV1, PLCβ2, and α-SMA, and upregulated the expression of TAS2R14 and Bcl-2 (P<0.05, P<0.01). ConclusionShegan Mahuangtang and its pungent and bitter Chinese herbs can reduce OVA-induced airway inflammation, downregulate the expression of TRPV1, PLCβ2, and α-SMA, and upregulate the expression of TAS2R14 and Bcl-2 in asthmatic rats. Moreover, bitter Chinese herbs outperformed pungent Chinese herbs, and the combination of them enhanced the therapeutic effect. It is suggested that Shegan Mahuangtang and its pungent and bitter Chinese herbs may ameliorate the OVA-induced airway inflammation by inhibiting TRPV1 and activating TAS2R14.