ObjectiveTo investigate the effects of chronic Aspergillus fumigatus (AF) exposure on the expression of platelet-derived growth factor (PDGF) and airway remodeling in the asthmatic rats. MethodsForty male Wistar rats were randomly divided into five groups (8 rats per group): group A (control group): sensitized with ovalbumin (OVA) and challenged with saline; group B (bronchial asthma group): sensitized and challenged with OVA to establish a chronic asthma model; groups C-E (bronchial chronic asthma + AF spores inhalation for 1 week, 3 weeks, or 5 weeks): the asthma rats were received intranasal inhalation of Aspergillus fumigatus spores for 1 week (Group C), 3 weeks (Group D), or 5 weeks (Group E). The concentrations of interleukin-5 (IL-5), interleukin-13 (IL-13), and transforming growth factor-beta (TGF-β) in bronchoalveolar lavage fluid (BALF) were measured using enzyme-linked immunosorbent assay (ELISA). Lung sections were stained with periodic acid Schiff (PAS) and Masson trichrome stain, and the images were analyzed morphometrically.The expression of PDGF were detected by immunohistochemistry and Western blot. ResultsThe levels of TGF-β (66.43 ± 2.78 ng/mL), IL-5 (33.49 ± 2.01 ng/mL), and IL-13 (50.78 ± 2.16 ng/mL) in BALF, as well as the extent of goblet cell hyperplasia (8.82 ± 1.95) and the degree of subepithelial collagen deposition (10.28 ± 2.48) in group B were higher than those in Group A (P<0.05). After inhalation of AF spores, the concentrations of TGF-β, IL-5, IL-13, along with the extent of goblet cell hyperplasia, and the degree of collagen deposition in the airways were increased progressively in group C, group D and group E (P<0.05). The expression of PDGF in the airways were upregulated in a dose-dependent manner. The extent of subepithelial collagen deposition and goblet cell hyperplasia in the airways were positively correlated with the expression of PDGF. ConclusionChronic exposure to Aspergillus fumigatus upregulates the expression of PDGF in the airways of bronchial asthma rats, thereby promoting airway remodeling.
