To investigate the effects of Sanzi Yangqin Decoction combined with Xiaoqinglong Decoction on lung tissue and peripheral blood CD4⁺ T lymphocytes in ovalbumin (OVA)-induced asthmatic rats.

Fifty SD rats were randomly divided into blank control group, asthma model group, dexamethasone group, Sanzi Yangqin Decoction + Xiaoqinglong Decoction group (double-drug combination), and dexamethasone + Sanzi Yangqin Decoction + Xiaoqinglong Decoction group (triple-drug combination), with 10 rats in each group (half male and half female). Except for the blank control group, asthma models were established by OVA sensitization and challenge in all other groups. After successful modeling, the treatment groups received corresponding drugs via intragastric administration for 2 weeks, while the blank control and model groups received equal volumes of normal saline. At the end of the experiment, resting minute ventilation (VE) and peak expiratory flow (PEF) were measured; the proportions of peripheral blood T helper 17 cells (Th17), regulatory T cells (Treg), T helper 1 cells (Th1), and T helper 2 cells (Th2) were detected by flow cytometry; serum levels of interferon-γ(IFN-γ), interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-10 (IL-10), and interleukin-17 (IL-17) were measured by ELISA; and the mRNA and protein expressions of epidermal growth factor receptor (EGFR), phosphorylated EGFR (p-EGFR), phosphatidylinositol 3-kinase (PI3K), phosphorylated PI3K (p-PI3K), protein kinase B (AKT), and phosphorylated AKT (p-AKT) in lung tissues were determined by qRT-PCR and Western blot.

(1) Pulmonary function: VE and PEF in the model group were significantly lower than those in the blank control group [ (85.32±10.25) ml vs. (165.25±26.36) ml, (2.87±0.13) ml/s vs. (5.30±0.39) ml/s, P<0.05]; all treatment groups showed increased VE and PEF (P<0.05), with the triple-drug combination group increasing VE and PEF to (150.32±18.42) ml and (4.64±0.25)ml/s, respectively. (2)Pulmonary fibrosis: The lung collagen fiber area in the model group was significantly higher than that in the blank control group [(49.55±5.65)% vs. (3.26±0.25)%, P<0.05]; the triple-drug combination group reduced it to (19.25±2.05)%. (3) T cell subsets: The model group showed imbalances in Th17/Treg and Th1/Th2 ratios (P<0.05); compared with the model group, the triple-drug combination group decreased Th17/Treg [ (1.90±0.19) vs. (0.45±0.04)] and increased Th1/Th2 [(0.89±0.11) vs. (6.29±0.57)] (P<0.05). (4) Cytokines: The model group had elevated IL-4, IL-10, and IL-17, and decreased IFN-γ and IL-2 (P<0.05); the triple-drug combination group reversed these changes (P<0.05). (5) Pathway molecules: The mRNA and protein expressions of EGFR, p-EGFR, PI3K, p-PI3K, AKT, and p-AKT in the model group were significantly increased (P<0.05); the triple-drug combination group reduced these expressions and decreased the p-EGFR/EGFR ratio compared with the model group. The improvements in all above indicators in the double-drug and triple-drug combination groups were superior to those in the dexamethasone group, and the triple-drug combination group was superior to the double-drug combination group (P<0.05).

Sanzi Yangqin Decoction combined with Xiaoqinglong Decoction ameliorates airway inflammation and pulmonary function abnormalities and restores Th1/Th2 and Th17/Treg immune balance in CD4⁺ T cells in asthmatic rats by inhibiting the aberrant activation of the EGFR-PI3K-AKT signaling pathway.