Mechanism of Eosinophilia IX. Induction of Eosinophilia in Rats by Certain Forms of Dextran

Production of Granulomatous Inflammation in Lungs of Rat Pups and Adults by Sephadex Beads

“…Mononuclear cells were the primary cells found in the lesion, but eosinophils and neutrophils also accumulated appreciably in the lesions and their surroundings. These results are consistent with previous reports (7,10). Examination of the BALF also revealed significant increased counts of eosinophils …”

“…When these particles initiated emboli in the pulmonary microvasculature, mononuclear cells, eosinophils, and neutrophils accumulated in the area and a granuloma was formed around the particle. The granuloma gradually expanded, and inflammatory cells infiltrated the adjoining pulmonary alveoli, respiratory tract, and blood vessels (7,8,10). In contrast, only a limited mononuclear infiltrate was found in the Sephadex-treated lungs of a mouse model (3,6).…”

“…In rat and guinea pig models, Sephadex beads administered intravenously or intratracheally can cause granulomatous lesions with considerable accumulations of eosinophils and neu-trophils in the lungs (7)(8)(9)(10). When these particles initiated emboli in the pulmonary microvasculature, mononuclear cells, eosinophils, and neutrophils accumulated in the area and a granuloma was formed around the particle.…”

Airway Hyper-Reactivity and Blood, Lung and Airway Eosinophilia in Rats Treated with Sephadex Particles

“…A requirement seemed to be that particles should be present of suffi cient size to embolise in the lung [7], Since then, blood eosinophilia has been produced in the rat by the intra venous injection of Sephadex [8] or protein-coated la tex particles [9], In the present study, we used Sepha dex particles and, in agreement with earlier workers [8], found that the eosinophilia was transient, peaking 5-7 days after the injection and returning to control values after 10 days, and that a second injection given after this produced a greater response than the first. The blood eosinophilia produced in rats by the intra venous injection of Trichinella larvae was accompan ied by a smaller increase in blood neutrophils and lymphocytes [5], but we found, in agreement with others, that the blood eosinophilia produced by the injection of Sephadex particles was more specific in that there was little effect on the numbers of other leu cocytes [2,8] and it was dose-dependent. There was also a dose-dependent increase in the numbers of eo sinophils in broncho-alveolar lavage (BAL) fluids taken from rats at the time of the peak in blood eosin ophilia, 5 days after the second injection of Sephadex, and, with the highest dose of Sephadex, about 16% of the cells were eosinophils.…”

Intratracheal Application of Sephadex in Rats Leads to Massive Pulmonary Eosinophilia without Bronchial Hyperreactivity to Acetylcholine

“…Stimulation of these nerve endings may then lead to the release of bronchoconstricting and pro-inflamma tory neuropeptides via an axon reflex [8], As well as toxic proteins, eosinophils can also release other pro-inflamma tory mediators such as leukotrienes [9] and reactive oxy gen species [10], Because of the possible pathogenetic sig nificance of pulmonary cosinophilia in asthma, it is impor tant that this effect is also found in an animal model for this disease. Walls and Beeson [11] were able to produce blood cosinophilia in rats by intravenous (i.v.) injection of Scphadex (cross-linked dextran) particles.…”