Asthma is characterized by inflammation, pulmonary remodeling and bronchial hyperresponsiveness. We have previously shown that treatment with angiotensin-(1-7) [Ang-(1-7)] promotes resolution of eosinophilic inflammation and prevents chronic allergic lung inflammation. Here, we evaluated the effect of treatment with the inclusion compound of Ang-(1-7) in hydroxypropyl β-cyclodextrin (HPβCD) given by inhalation on pulmonary remodeling in an ovalbumin (OVA)-induced chronic allergic lung inflammation. Mice were sensitized to ovalbumin (OVA; 4 injections over 42 days, 14 days apart) and were challenged 3 times per week, for 4 weeks (days 21-46). After the 2nd week of challenge, mice were treated with Ang-(1-7) by inhalation (4.5 μg of Ang-(1-7) included in 6.9 μg of HPβCD for 14 days, i.e. days 35-48). Mice were killed 72 h after the last challenge and blood, bronchoalveolar lavage fluid (BALF) and lungs were collected. Histology and morphometric analysis were performed in the lung. Metalloproteinase (MMP)-9 and MMP-12 expression and activity, IL-5, CCL11 in the lung and plasma IgE were measured. After 2 weeks of OVA challenge there was an increase in plasma IgE and in inflammatory cells infiltration in the lung of asthmatic mice. Treatment with inhaled administration of Ang-(1-7)/HPβCD for 14 days reduced eosinophils, IL5, CCL11 in the lung and plasma IgE. Treatment of asthmatic mice with Ang-(1-7)/HPβCD by inhalation reversed pulmonary remodeling by reducing collagen deposition and MMP-9 and MMP-12 expression and activity. These results show for the first time that treatment by inhalation with Ang-(1-7) can reverse an installed asthma, inhibiting pulmonary inflammation and remodeling.
Keywords: Immunoglobulin E; OVA challenge; Renin angiotensin system; Resolution of inflammation.
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