Effects of the combined extracts of Herba Epimedii and Fructus Ligustrilucidi on airway remodeling in the asthmatic rats with the treatment of budesonide

Abstract

Background: Asthma is characterized by chronic airway inflammation, leading to structura1 changes in the airway, collectively termed airway remodeling. Airway remodeling is thought to contribute to airway hyper responsiveness and irreversible airflow limitation. The combination of Herba Epimedii (HE) and Fructus Ligustri Lucidi (FLL) decoction and the systemic administration of glucocorticoids (GC) had a synergistic inhibitory action on airway inflammation in the asthmatic model rats. However, the effects of the combination on airway remodeling have not been studied and compared. In the present study, we investigated the effects of the co-administration of combined extracts of HE and FLL with inhaled GC (budesonide) on airway remodeling in the rat asthmatic model induced by ovalbumin (OVA). Methods: Male Sprague-Dawley rats were sensitized to intraperitoneal OVA followed by repetitive OVA challenge for 7weeks. Treatments included extracts of HE and FLL (Extracts for short, 100mg/kg by gastric perfusion), budesonide (1mg budesonide suspension in 50ml sterile physiological saline, 3 rats in an ultrasonic nebulizer by nebulized inhabation with a flow of 1.6ml/min for 30min), and co-administration of extracts of HE and FLL with budesonide (Co-administration for short) for 4weeks. Lung histomorphometry and bronchoalveolar lavage fluid (BALF) cell count were assessed 24h after the final OVA challenge. Levels of interleukin (IL)-4, IL-5 and IgE were measured by ELISA. Expressions of Collagen I and Collagen III were tested by immunohistology. Expressions of transforming growth factor (TGF) -β1, TGF-β2 and Smads mRNA were measured by quantitative real-time PCR. Results: Extracts, budesonide and Co-administration significantly reduced allergen-induced increases in the serum levels of IL-4, IL-5 and IgE, the number of eosinophils in BALF, goblet cell hyperplasia, Collagen III integral optical density (IOD) and the mRNA expression of TGF-β2 and Smad2. Extracts and Co-administration could depress the IOD level of Collagen I and the positive area of Collagen I and Collagen III. Budesonide and Co-administration significantly alleviated the thickening of airway wall. Only Co-administration significantly decreased collagen deposition according to the morphometry of Masson's-stained lung sections, the thickening of airway smooth muscle layer, the number of lymphocytes in BALF and the mRNA expression of TGF-β1 and Smad3, and this was associated with a significant increase in levels of Smad7 mRNA. Conclusions: The findings suggested that the combination of budesonide and the herbal extracts had a better synergistic effect on airway remodeling in OVA-reduced asthma rats than the single use of budesonide.