Methods: Adult female rhesus macaques (n=6) were nebulized for 7 consecutive days and studied 1 day before, 1 day post treatment (dpt), and 4 dpt. Differential cell counts and immune phenotyping (from blood, bronchoalveolar lavage [BAL] and thoracic lymph nodes [LN]) were performed by flow cytometry and oxidative stress-related gene and protein expression was assessed from the lung tissue upon necropsy (7dpt).
Results: Eosinophils, neutrophils, dendritic cells (DCs), CD4+, and CD8+ T cells expanded in the blood and were recruited to the airways 1-4 dpt in both vehicle and statin-treated groups. pDCs, pro-inflammatory CD16+, CD4+ and CD8+ T cells migrated to the LN by 5 dpt in both groups, but in reduced levels in statin-treated animals. A trend of decreased activation of CD16+ DCs and plasmacytoid DCs (pDCs) was observed in the lung and LN of statin-treated animals. NRF-2-dependent antioxidant protein levels were elevated in lung tissue in statin-treated compared to vehicle-treated groups.
Conclusions: Immune activation was observed in both the airways and periphery following nebulization exposure to vehicle alone, with a tendency towards reduction of inflammation in statin-treated groups. This study establishes a method to evaluate nebulization-induced effects that can be extended to preclinical testing of inhaled therapies.