Morphological and Structural Changes in Lung Tissue Infected by Paracoccidioides brasiliensis: FTIR Photoacoustic Spectroscopy and Histological Analysis

Abstract

This study evaluated physical, chemical and morphological changes in lungs of mice infected with Paracoccidioides brasiliensis. The animals were inoculated with 0.1 mL of fungal suspension of the P. brasiliensis 18 isolate and were euthanized 1, 2, 4 and 8 weeks after inoculation. The upper left lobe of the lung was isolated, fixed and processed for paraffin embedding. The sections were stained with H&E for histopathological study, with Gomori-Grocott to locate and identify the fungus, and with TUNEL immunostaining to detect the occurrence of programmed cell death. The lower and middle right lobes were analyzed by Fourier Transform Infrared Photoacoustic Spectrocopy (FTIR-PAS) to investigate physical and chemical features of the infected lungs. The results showed that lungs infected by P. brasiliensis underwent structural changes that varied according to the time period analyzed, and that changes in the absorption bands of different chemical groups resulted from these morphological changes. The results suggest that the combination of FTIR-PAS spectroscopy with morphological evaluation is an effective procedure for the study of paracoccidioidomycosis, one of the most important systemic mycoses that can damage the lung architecture and consequently impair the respiratory function.

Characterization of curdlan produced by Agrobacterium sp. IFO 13140 cells immobilized in a loofa sponge matrix, and application of this biopolymer in the development of functional yogurt

“…12 The interactions between microorganisms and loofa sponges can be analyzed by Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectrometry, because it allows evaluation of the physical/chemical structure of materials by detecting absorption bands from molecular chemical groups and the occurrence of their structural modifications. 12,20 In the present study, Agrobacterium sp. IFO 13140 cells were immobilized on a loofa sponge and subjected to five consecutive cycles for curdlan production, and the interaction between the cells and the matrix was determined.…”

“…Studies that have analyzed interactions between microorganisms and loofa sponges are still scarce . The interactions between microorganisms and loofa sponges can be analyzed by Fourier transform infrared‐attenuated total reflectance (FTIR‐ATR) spectrometry, because it allows evaluation of the physical/chemical structure of materials by detecting absorption bands from molecular chemical groups and the occurrence of their structural modifications …”

Combination of Histopathology and FT‐Raman Spectroscopy for the Study of Experimental Paracoccidioidomycosis in the Spleen

“…Pb can cause morphofunctional changes resulting from the invasion, adhesion and residence of the microorganism in the organs . In the lungs, PCM leads to the development of fibrosis, represented by the expressive expansion of the collagen fibers in the pulmonary parenchyma, a phenomenon that can evolve and lead a patient to develop respiratory insufficiency .…”

“…For example, previous studies demonstrated their relevance in this area when used in modified arrangements, allowing coupling the methods with both optical biopsy or in situ optical fiber probes . These techniques can characterize the functional groups of organic compounds in tissues and enable a tissue in a physiological state to be distinguished from another in a pathological state . For this reason, they are powerful tools for the analysis of biological materials and may represent an alternative and advantageous procedure for diagnosis of infectious diseases, especially in experimental investigations.…”

“…Recently the histopathological changes resulting from Pb infection were correlated with molecular alterations detected by Fourier Transform Infrared Spectroscopy (FTIR) . The Raman and FTIR vibrational spectroscopies are techniques of growing interest for evaluation of the biochemical composition of tissues, especially for diagnostic purposes.…”