Morphologic Organization of Pulmonary Granulomas in Mice Infected with Paracoccidioides brasiliensis

• Published in: The American journal of tropical medicine and hygiene Vol. 80; no. 6
• Main Authors: Da Silva, FC, Svidzinski, TIE, Patussi, E V, Cardoso, C P, De Oliveira Dalalio, MM, Hernandes, L
• Format: Journal Article
• Language: English
• Published: 01-06-2009
• Subjects: Apoptosis; Collagen; Colony-forming cells; Fibers; Fibrosis; Granuloma; Infection; Inflammation; Inoculation; Lung; Macrophages; Paracoccidioides brasiliensis; silver nitrate
• ISSN: 0002-9637

A morphologic study of the lungs was carried out in Swiss mice infected with yeast isolated from Paracoccidioides brasiliensis (Pb18). The lung was processed 1, 2, 4, and 8 weeks after inoculation for histologic staining with hematoxylin and eosin (H&E), methenamine silver nitrate (Gomori-Grocott), and picrosirius to qualitative and quantitative analyses of the granulomas and the presence of fungal lesions. The numbers of CFUs/g counted in the lungs were 189.8 c 20.64, 353.6 c 46.21, 547.2 c 108.1, and 295.2 c 89.17 in the first, second, fourth, and eighth weeks, respectively. One week after infection, inflammatory cells and reticular and collagens fibers, the latest typical of fibrosis, were detected. After 2 and 4 weeks, a progressive intensification of the infection and fibrosis was observed, but in week 8 a more organized granuloma was evident, with macrophages, epithelioid cells, and yeasts in the central portion, and intense peripheral basophilia. Pycnotic structures typical of apoptotic bodies were observed in weeks 1 and 8. The different histologic staining used acted as a fundamental tool for the study of the morphologic organization of granuloma formation.