HuangLong oral liquid alleviates cough variant asthma in mice via inhibiting M2 macrophage chemotaxis and polarization by regulating the PI3K/AKT/ERK pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Huanglong Oral Liquid (HLOL), a traditional Chinese medicine formulation, has been clinically employed for decades in paediatric cough variant asthma (CVA) management, demonstrating efficacy in symptom relief. Nevertheless, the molecular mechanisms governing the therapeutic effects of HLOL remain incompletely characterised.

AIM OF THE STUDY: This study seeks to decipher how HLOL alleviates Ovalbumin-induced airway inflammation and hyperresponsiveness in murine CVA models.

MATERIALS AND

METHODS

The main chemical components of HLOL were identified using liquid chromatography tandem mass spectrometry (HPLC-MS). OVA was used to establish a CVA mouse model, and the anti-inflammatory and anti-airway hyperresponsiveness therapeutic effects of HLOL were evaluated using pathological staining, capsaicin inhalation experiment, and lung function tests. Through RNA-sequencing (RNA-seq) revealed the potential mechanism of HLOL in regulating M2 recruitment and polarization in the lung tissues of CVA mice, which was further verified via in vivo and in vitro experiments using quantitative polymerase chain reaction, enzyme linked immunosorbent assay, western blot, immunofluorescence staining, immunohistochemistry for paraffin-embedded sections, and cell migration assays.

RESULTS

HPLC-MS analysis identified 40 potential active ingredients. HLOL improved lung function in CVA mice, attenuated airway hyperresponsiveness, and reduced both inflammatory cell infiltration and mucus production in the lung tissue. The intervention additionally decreased macrophage aggregation near the airway and inhibited M2 macrophage polarization, thus maintaining a dynamic balance of M1/M2 macrophages in CVA mice. RNA-seq implicated the PI3K/AKT/ERK and chemokine signalling axes as key mediators for the effect of HLOL on macrophage recruitment and polarization, which was subsequently validated through comprehensive in vivo and in vitro experiments.

CONCLUSIONS

HLOL reduces macrophage chemotaxis and M2 polarization near the airway of CVA mice by regulating the PI3K/AKT/ERK and chemokine signalling pathways, thereby inhibiting airway inflammation and hyperresponsiveness in CVA mice.