Stigmasterol extracted from Coix lacryma-jobi ameliorates COPD lung injury via PPARγ-metabolic reprogramming-M2 polarization axis

Abstract Objective To investigate the mechanism of stigmasterol, an extract from Coicis Semen, in treating rats with a chronic obstructive pulmonary disease (COPD) model. Methods Forty healthy male SD rats (body weight:120±10 g) were randomly divided into four groups (n=10) using a random number table: blank control (NC) group, model (Mock) group, Stigmasterol group (stigmasterol 20 mg/kg), and stigmasterol+GW9662 group (stigmasterol 20 mg/kg+peroxisome proliferator-activated receptor γ (PPARγ) antagonist GW9662 1 mg/kg). The COPD rat model was established by smoke exposure combined with intratracheal instillation of lipopolysaccharide (LPS, 1 mg/kg). After 14 d of intervention, alveolar macrophages were isolated. M1/M2 polarization was analyzed by flow cytometry; PPARγ expression was detected using qRT-PCR, Western blot, and ELISA; macrophage oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were measured with a Seahorse XF Analyzer; and lung tissue pathology and macrophage infiltration were observed via HE staining and immunohistochemistry. Results Compared with the NC group, the Mock group exhibited a significantly increased M1/M2 ratio (P