Image analysis for the role of pigmented macrophages in fully formed granulomas in the liver of Syrian hamsters experimentally infected with schistosoma mansoni

ABSTRACT

Pigmented macrophages [PMs] exhibited very prominent role in attacking schistosome eggs and regulating the histoarchitecture of granulomateous reaction during schistosome infection in liver of Syrian hamsters. Macrophages in response to soluble egg antigens [SEA] are attracted to the egg shell primarily then to alive miracidium. These cells also have a potential role in dissolving egg shell and opening the gate for other inflammatory cells to destroy the live miracidia. In some hosts, it has been found that PMs were the only cells attacking schistosome eggs in absence of other inflammatory cells. They also participate in formation of fibrotic capsule around granulomas formed and building the fibrotic scaffold in liver parenchyma. The massive number of PMs attracted to site of trapped schistosome eggs suggested the close relationship between PMs and SEA. The formation of collagen fibers belonging to the family of glycoproteins is stimulated by PMs which lost their roundness and became stretched and in cooperation with other inflammatory cells; they enhance the process of granuloma formation. Image analysis [IA] software program [2008] used herein revealed that average percent of PMs to total inflammatory cells were 2.1 and 6.3 in both control and infected hamsters respectively [P=0.001]. Differences between average values of length, width, perimeter, radius and height were more significant in infected hosts than non infected ones [P=0.001] for all parameters. The average percent of roundness of PMs in controls were 3.77 while it was 2.52 in infected hamsters by mean that some cells lost their roundness and became spindle shaped as well as collagen fibers [P=0.001]. This analysis may lead to better understanding for the processes of granuloma formation and the role played by PMs .The above findings suggest that PMs induce innate proinflammatory response and thus control the outcome of immunopathology in schistosomiasis