Collagen arrangement in hepatic granuloma in mice infected with Schistosoma mansoni: dependence on fiber radiation centers.

H.L Lenzi,J.A Lenzi,H Schechtman,B.S Vale,M.S Panasco,E Kimmel,M Pelajo-Machado

doi:10.1590/s0100-879x1999000500018

Abstract

The collagen structure of isolated and in situ liver granuloma from Swiss Webster mice infected with Schistosoma mansoni was sequentially and three-dimensionally analyzed during different times of infection (early acute, acute, transitional acute-chronic, and chronic phases) by laser scanning confocal microscopy and electron scanning variable vacuum microscopy. The initial granuloma structure is characterized by vascular collagen residues and by anchorage points (or fiber radiation centers), from where collagenous fibers are angularly shed and self-assembled. During the exudative-productive stage, the self-assembly of these fibers minimizes energy and mass through continuous tension and focal compression. The curvature or angles between collagen fibers probably depends on the fibroblastic or myofibroblastic organization of stress fibers. Gradually, the loose unstable lattice of the exudative-productive stage transforms into a highly packed and stable architecture as a result of progressive compactness. The three-dimensional architecture of granulomas provides increased tissue integrity, efficient distribution of soluble compounds and a haptotactic background to the cells.

Highlights

A granuloma is characterized by the presence of clusters of cells of the mononuclear phagocyte series with or without other cell types [1]
As previously described [15], that the granuloma stage in the liver is preceded by a lytic pre-granulomatous phase which produces a spherical space by destruction of the parenchyma for the final establishment and organization of the lesion
The three-dimensional tissue architecture of the granuloma, as observed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), presents extracellular matrix (ECM) fibers which are initially arranged in a mesh pattern (Figures 2 and 3), evolving to a final and compact concentric arrangement (Figure 4)

Summary

Introduction

A granuloma is characterized by the presence of clusters of cells of the mononuclear phagocyte series with or without other cell types [1]. Granulomas function as little organs, presenting stages of maturation and involution during their development, and final disappearance.

Results

Conclusion